Entries |
Document | Title | Date |
20080204136 | Distortion compensation apparatus - A distortion compensation apparatus includes an amplifier for amplifying an input signal, a calculation unit for obtaining a distortion compensation coefficient of the amplifier corresponding to an amplitude level of the input signal, based on the input signal input to the amplifier and an output signal output from the amplifier, a memory for storing the distortion compensation coefficient, obtained by the calculation unit, into a write address being made to correspond to the input signal amplitude level, a distortion compensation processing unit for reading out the distortion compensation coefficient from the readout address of the memory, and for performing distortion compensation processing of the input signal using the distortion compensation coefficient, and an address generator for generating the write address and the readout address, based on the input signal amplitude level. | 08-28-2008 |
20080211576 | Linearization of RF Power Amplifiers Using an Adaptive Subband Predistorter - Predistorting an input signal prior to amplification in an RF power amplifier ( | 09-04-2008 |
20080218262 | PREDISTORTION WITH ASYMMETRIC USAGE OF AVAILABLE BANDWIDTH - The invention relates to a method for performing predistortion of a radio frequency signal, said radio frequency signal comprising a wanted signal and a first and a second intermodulation distortion signal sideband, comprising: defining a predistortion window, positioning said predistortion window asymmetrically around said radio frequency signal, predistorting said radio frequency signal within the positioned predistortion window. | 09-11-2008 |
20080238544 | AMPLIFIER PRE-DISTORTION SYSTEMS AND METHODS - A method of optimizing performance of a multiple path amplifier includes: splitting an input signal to derive a respective sub-signal for each branch of the multiple path amplifier; independently pre-distorting each sub-signal using a known performance characteristic of its associated branch of the multiple path amplifier; and supplying each pre-distorted sub-signal to its associated branch of the multiple amplifier. | 10-02-2008 |
20080252371 | FEEDFORWARD AMPLIFIER - There is disclosed a feedforward amplifier for compensating for distortion produced in an amplifier. The feedforward amplifier controls the phase in a vector adjuster effectively. The feedforward amplifier has a first variable phase shifter PH | 10-16-2008 |
20080290939 | Method and apparatus for distortion correction of RF amplifiers - A method of reducing distortion in the output of an amplifier is provided. The method comprises subtractively combining baseband error signals with the appropriate phase shift with baseband input signals, the baseband error signals generated by subtractively combining delayed fed-forward portions of the baseband input signals with baseband converted portions of a fed-back amplified output signal, the amplified output signal being a distorted replica of combined up-converted baseband input signals. The baseband error signals being filtered prior to the combining function, and also providing inputs to a controller which adjusts active elements of the amplification and fed-back paths in order to minimize the distortion within the output of the amplifier. | 11-27-2008 |
20080297247 | Method and apparatus for distortion correction of RF amplifiers - A method of reducing distortion in the output of an amplifier is provided. The method comprises subtractively combining an error signals with the appropriate phase shift with input signals to be amplified. The error signal being generated by subtractively combining a fed-forward portion of the input signal with a portion of the fed-back amplified output signal, and signal processing applied to it between its generation and application to correcting the input signal in the baseband domain. The error therefore being down-converted, filtered, and up-converted in the feedback path. The filtered baseband error signal components providing inputs to a controller which adjusts active elements of the amplification and feedback path in order to minimize the distortion within the output of the amplifier. | 12-04-2008 |
20080309405 | Power Amplifier Pre-Distortion - The present invention is directed to systems and methods for reducing the distortion of power amplifiers. In particular, methods and systems are described that enable a determination of a pre-distortion correction signal to be determined, which when added to the nominal signal, a reduction in the distortion of the power amplifier results. In addition, methods and systems are described that enable calibration of individual power amplifiers to be accomplished for use with the above described approach. More specifically, the methods and systems are described for use in a MIMO application. These approaches may be applied to on-chip power amplifiers, off-chip power amplifiers, or any combination thereof. | 12-18-2008 |
20080315947 | Controller-Assisted Method and Controller-Assisted Device for Determining a Characteristic of a Compensation Member in a Level Control Circuit - In a controller-assisted device for determining a characteristic of a compensation element in a level control circuit, the compensation element is serially mounted inside the level control circuit for a high-frequency signal (SHF) in a signal channel with respect to said signal channel. The characteristic of the compensation element has a characteristic which the inverse of the non-linear transmission characteristic of the signal channel in the event of ideal compensation. In the controller-assisted method for the determination of a characteristic of the compensation element in a level control circuit, each ordinate value of the characteristic of the compensation element arises, in the event of a bridged compensation element, from the corrective signal value (P | 12-25-2008 |
20090015325 | Method and apparatus for pre-conditioning an electrical signal - Iterative pre-conditioning of an electrical signal for supply to an amplifier, comprising: a first pre-conditioning iteration comprising limiting the amplitude of the electrical signal to produce a limited signal; generating a difference signal for subtracting the electrical signal from the limited signal; and generating an output signal by subtracting the difference signal from the limited signal; at least one further iteration comprising the steps of: Limiting the amplitude of the output signal of the previous iteration to produce a subsequent limited signal; generating a subsequent difference signal by subtracting the electrical signal from the subsequent limited signal; and generating an output signal by subtracting the subsequent difference signal from the subsequent limited signal. | 01-15-2009 |
20090015326 | DISTORTION COMPENSATION APPARATUS - A distortion compensation apparatus includes distortion generating means for generating distortions to compensate for a distortion generated in an amplifier | 01-15-2009 |
20090027119 | Reduced distortion radio frequency amplifiers - A radio frequency power amplifier system includes a power amplifier coupled to an input signal and configured to provide an output signal at a radio frequency; a signal cancellation system coupled to the input signal, and a first feedback signal, which is based on the output signal, and configured to provide an error signal with a reduced level of the input signal; and a feedback control system coupled to the error signal and configured to provide a correction signal that is used to reduce distortion in the output signal. A corresponding method includes amplifying in a forward path an input signal to provide an output signal at a radio frequency; combining a reference and a first feedback signal to provide an error signal with a reduced level of the input signal; providing, responsive to the error signal and in a. feedback control system that is separate from the forward path, a correction signal; and then using the correction signal to reduce distortion in the output signal. | 01-29-2009 |
20090033418 | Training sequence and digital linearization process for power amplifier - A training sequence and digital linearization process for a power amplifier are provided. In particular, a system for maintaining linear operation of an amplifier is includes an estimation component configured to determine compensation coefficients. The system further includes a digital pre-distorter configured to compensate for non-linear operation of the amplifier based on the compensation coefficients. The compensation coefficients are determined based on a training sequence signal having a time synchronization portion and a linearization sequence portion. | 02-05-2009 |
20090051424 | ACTIVE CIRCUITS WITH LOAD LINEARIZATION - Active circuits with active loads linearized via distortion cancellation are described. In one design, an apparatus includes a first stage and a load stage. For an amplifier, the first stage amplifies an input signal and provides an output signal having a larger signal level. For a mixer, the first stage mixes an input signal with an LO signal and provides an output signal. The load stage provides an active load for the first stage and is linearized by canceling distortion generated by the active load. In one design, the load stage includes a first transistor that provides the active load and generates distortion due to its nonlinearity. The load stage further includes at least one transistor that generates a replica of the distortion from the first transistor. The distortion replica is used to cancel the distortion from the first transistor. The first stage may also be linearized with distortion cancellation. | 02-26-2009 |
20090051425 | PREDISTORTION SYSTEM AND METHOD BASED ON LOOK UP TABLE INTERPOLATION - A system comprising a pre-power amplifier and a hardware device which is configured to predistort an amplitude input signal by comparing interpolated data places, determined by comparing the input signal with data from a LUT, coming from a LUT with the amplitude input signal and choosing the closest input data place to the amplitude input signal to produce an amplitude predistortion output signal. The LUT contains predistortion data associated with the pre-power amplifier. The amplitude input signal is multiplied and scaled prior to being compared with the data in the LUT. A second LUT is used to predistort a phase input signal and the phase predistortion output signal is combined in the pre-power amplifier with the amplitude predistortion output signal. The system may be implemented in a mobile communications device. | 02-26-2009 |
20090051426 | Large-Dynamic-Range Lookup Table for a Transmitter Predistorter and System and Method Employing the Same - A predistorters for use with a nonlinear element and methods of predistorting for a nonlinear element for use in a 3G, e.g., WCDMA transmitter. In one embodiment, the predistorter includes: (1) a lookup table having non-uniformly spaced entries therein, (2) a compander configured to compand an input signal based on a nonlinearity of the nonlinear element to address the entries and (3) an interpolation offset calculation circuit associated with the lookup table and configured to produce an output based on a value of the input signal and a linear interpolation involving at least two entries from the lookup table. | 02-26-2009 |
20090058521 | SYSTEM AND METHOD OF DIGITAL LINEARIZATION IN ELECTRONIC DEVICES - A method, apparatus, and computer program product to reduce nonlinear signal distortion of a primary signal within an electronic device is provided. An example method includes the steps of: applying at least one stimulus signal to excite distortion; analyzing nonlinear effects in the distorted stimulus signal; modeling distortion as a function of the stimulus signal; and creating a correction signal using the distortion model and the primary signal. | 03-05-2009 |
20090072900 | APPARATUS AND METHOD FOR COMPENSATING FOR NONLINEARITY IN PORTABLE COMMUNICATION TERMINAL - An apparatus and method for compensating for nonlinearity of a portable communication terminal are provided. The apparatus includes a modem for modulating Transmission (Tx) data, a Digital Pre-Distortion (DPD) mode controller for obtaining power level information and for determining a power on/off state of a DPD unit by using the obtained information in the Tx mode, and the DPD unit for outputting the modulated data input from the modem without performing a DPD operation when power is off, and for outputting the modulated data input from the modem by performing the DPD operation when power is on. | 03-19-2009 |
20090072901 | POWER AMPLIFIER - A power amplifier of the present invention includes a distributor ( | 03-19-2009 |
20090085658 | ANALOG POWER AMPLIFIER PREDISTORTION METHODS AND APPARATUS - An embodiment of the invention is a predistortion approach to linearize a power amplifier by using one or more analog multiplier(s) and a DSP-based processor. For the analog embodiment, the inherent nature of the analog circuitries allows digital predistortion processing structured directly at the RF band, and enables a single power amplifier to support multi-modulation schemes, multi-carriers and multi-channels. As a result, the predistortion architecture is particularly suitable for wireless transmission systems, such as base-stations, repeaters, and indoor signal coverage systems. The wireless system performance can be improved and upgraded just by using the new PA module rather than change or rebuild new subsystem in existing base station. The analog embodiment can also mix and match its analog multipliers with other analog components such as phase splitters, phase shifters, attenuators, filters, couplers, mixers, low-noise amplifiers, buffers, envelope detectors, and etc., to provide additional features. | 04-02-2009 |
20090096521 | POWER AMPLIFIER PREDISTORTION METHODS AND APPARATUS USING ENVELOPE AND PHASE DETECTOR - An embodiment of the invention is a predistortion approach to linearize a power amplifier without frequency conversion of the RF signals by using envelope and phase detectors to detect the error to be corrected, and then one or more analog multiplier(s) and a DSP-based processor. For the analog embodiment, the inherent nature of the analog circuitries allows digital predistortion processing structured directly at the RF band, and enables a single power amplifier to support multi-modulation schemes, multi-carriers and multi-channels. As a result, the predistortion architecture is particularly suitable for wireless transmission systems, such as base-stations, repeaters, and indoor signal coverage systems. The wireless system performance can be improved and upgraded just by using the new PA module rather than change or rebuild new subsystem in existing base station. The analog embodiment can also mix and match its analog multipliers with other analog components such as phase splitters, phase shifters, attenuators, filters, couplers, mixers, low-noise amplifiers, buffers, envelope detectors, and etc., to provide additional features. | 04-16-2009 |
20090096522 | AMPLIFIER CIRCUIT - An amplifier circuit easily suppresses an intermodulation distortion signal incident to amplification. An input signal is class A amplified to be | 04-16-2009 |
20090115513 | Predistorter - The invention aims to converge predistortion coefficients efficiently in a predistorter adapted to compensate for distortion generated in an amplifier. Level detection means ( | 05-07-2009 |
20090121788 | SYSTEM AND METHOD FOR SELF-CANCELLATION OF NTH-ORDER INTERMODULATION PRODUCTS - A method for reducing distortion in a nonlinear device whereby n | 05-14-2009 |
20090134940 | BALANCED AMPLIFIER AND ELECTRONIC CIRCUIT - A balanced amplifier ( | 05-28-2009 |
20090140806 | DISTORTION-COMPENSATION AMPLIFICATION APPARATUS AND DISTORTION COMPENSATION METHOD - Distortion-compensation amplification apparatus that can obtain an appropriate error vector magnitude without increasing power consumption and can suppress the distortion of a transmission signal appropriately. A distortion compensation section applies distortion compensation to the transmission signal. An amplification section amplifies the transmission signal to which distortion compensation has been applied by the distortion compensation section. A frequency component calculation section calculates the power of frequency components of the transmission signal amplified by the amplification section. A peak suppression section suppresses the peak value of the transmission signal input to the distortion compensation section in accordance with the power of the frequency components calculated by the frequency component calculation section. | 06-04-2009 |
20090146736 | Baseband-Derived RF Digital Predistortion - A baseband-derived RF predistortion system using a lookup table having coefficients extracted at baseband and then applied at RF by means of a vector modulator. The architecture combines the narrowband advantage of envelope predistortion with the accuracy of baseband predistortion, and including compensation for memory effects. A polynomial-based alternative is also described. | 06-11-2009 |
20090160549 | Linearised Power Amplifier - A linearised power amplifier including a predistorter and a feedforward circuit is described. By using both a predistorter and a feedforward cancellation system the linearisation of the amplifier is increased. The accuracy of the amplified signal may be further improved by training the predistorter using the error signal produced by the feedforward cancellation system. Improved accuracy in the lineariser results in a reduction in the power requirement of the error amplifier and a relaxation in the phase, amplitude and delay accuracy of the feedforward loop. | 06-25-2009 |
20090160550 | PREDISTORTER - A predistorter for correcting distortion caused by a memory effect in amplifying a signal by an amplifier is provided. In the memory PD | 06-25-2009 |
20090174476 | NOISE REDUCTION CIRCUIT FOR CANCELING LEAKAGE SIGNAL - In a noise reduction circuit, a transistor circuit amplifies an input signal and outputs an output signal with supply of power from the DC voltage source via a power supply line circuit. The canceling signal adding circuit acquires and attenuates a part of the output signal, to generate a canceling signal having a phase substantially opposite to a phase of a leakage signal leaking to the power supply line circuit, and having an amplitude substantially the same as an amplitude of the leakage signal. | 07-09-2009 |
20090189691 | METHOD AND APPARATUS FOR REDUCING INTERMODULATION DISTORTION IN AN ELECTRONIC DEVICE HAVING AN AMPLIFIER CIRCUIT - An electronic device includes an amplifier circuit coupled to a linearizer. The amplifier circuit may receive a first input signal including first and second frequencies and generate a first output signal including a delta frequency signal at a delta frequency, which is the difference between the first frequency and the second frequency. The linearizer includes a signal detector circuit, a current-mirror circuit, a low pass filter, a phase shifter, and a bias circuit. The signal detector circuit may generate a second output signal. The current-mirror circuit may adjust an amplitude of a signal. The low pass filter may eliminate a portion of the second output signal having frequencies greater than the delta frequency. The phase shifter may generate a feedback signal corresponding to the delta frequency signal. An amplitude and/or a phase of the feedback signal is different from an amplitude and/or a phase of the delta frequency signal. | 07-30-2009 |
20090189692 | PREDISTORTER - A predistorter for correcting distortion caused by a memory effect in amplifying a signal by an amplifier is provided. In the memory PD | 07-30-2009 |
20090195309 | DISTORTION COMPENSATOR APPARATUS, AMPLIFIER APPARATUS, TRANSMITTER, AND METHOD OF COMPENSATING DISTORTION - This distortion compensator apparatus is a distortion compensator apparatus compensating nonlinearity of an amplifier and includes: a memory storing a compensation parameter used for correcting an input signal of the amplifier; a compensator correcting the input signal of the amplifier based on the compensation parameter; and an update controller updating the compensation parameter according to an operation state of the amplifier. | 08-06-2009 |
20090219088 | APPARATUS AND METHOD FOR CORRECTING NON-LINEAR DISTORTION BASED ON CHARACTERISTIC MODELING OF HIGH POWER AMPLIFIER - An apparatus for correcting a non-linear distortion includes a pre-distorter for pre-distorting a transmit signal inputted from an external apparatus based on pre-distortion characteristics outputted from a pre-distortion characteristic predictor; a modulator for modulating the pre-distorted signal to thereby generate a modulated signal; a frequency up-converter for up-converting a frequency of the modulated signal to thereby generate an up-converted signal; a high power amplifier for amplifying the up-converted signal to a high power amplified signal; a frequency down-converter for down-converting a frequency of the high power amplified signal, thereby generate a down-converted signal; a demodulator for demodulating the down-converted signal, to thereby generate a demodulated signal; a high power amplifying characteristic predictor for predicting characteristics of the high power amplifier based on the pre-distorted signal and the demodulated signal; and a pre-distortion characteristic predictor for predicting the pre-distortion characteristics based on the pre-distorted signal and the predicted high power amplifying characteristics. | 09-03-2009 |
20090237158 | ELECTRONIC DEVICE HAVING A PREDISTORTION FILTER AND RELATED METHODS - An electronic device includes a nonlinear power amplifier, a predistortion coefficient calculator, and a memory polynomial predistortion filter coupled to the nonlinear power amplifier and to the predistortion coefficient calculator. The memory polynomial predistortion filter may include a plurality of finite impulse response (FIR) filter stages, and a summer coupled to the plurality of FIR filter stages. The FIR filter stages may functionally operate in parallel or may include a series of FIR filters coupled in parallel. | 09-24-2009 |
20090243720 | AMPLIFIERS WITH NEGATIVE CAPACITANCE CIRCUITS - Provided herein are amplifiers including negative capacitance circuits for reducing distortion resulting from a gate-source (or base-emitter) capacitance of output stages of such amplifiers. Such a negative capacitance circuit is connected in parallel with the gate-source (or base-emitter) capacitance of the output stage to shunt the gate-source (or base-emitter) capacitance and thereby reduce distortion. Also provided herein are methods for use with amplifiers including an output stage, including connecting a negative capacitance circuit in parallel with a base-emitter capacitance of the output stage. | 10-01-2009 |
20090251211 | FEEDFORWARD LINEARIZATION OF RF POWER AMPLIFIERS - RF amplifier system ( | 10-08-2009 |
20090256631 | Providing pre-distortion to an input signal - In one implementation, the present invention includes a diode device to receive an incoming radio frequency (RF) signal to be amplified in a gain device of an amplifier and to provide a pre-distorted signal. Based on this pre-distorted signal, the gain device can output an amplified RF signal having substantial linearity to the incoming RF signal. | 10-15-2009 |
20090256632 | METHOD AND APPARATUS FOR REDUCING FREQUENCY MEMORY EFFECTS IN RF POWER AMPLIFIERS - The present invention relates to a predistorter for reducing memory effects in RF power amplifiers. The invention also relates to a method for reducing memory effects in RF power amplifiers and to a base station including such a predistorter. A predistorter according to the invention includes first means ( | 10-15-2009 |
20090289706 | Cube coordinate subspaces for nonlinear digital predistortion - A method or corresponding apparatus relates to a mathematical approach to efficiently search for and localize regions in a multi-dimensional signal space to enable inversion of power amplifier nonlinearities with a significant reduction in computational complexity and an efficient hardware implementation. To linearize a wideband power amplifier, an example embodiment of the present invention may represent a response of the wideband power amplifier using coefficients in a cube coefficient subspace, and search over the full multi-dimensional subspace according to an optimization criterion in order to identify a vector of cube coefficient subspace coefficients. The vector of coefficient subspace coefficients may be used to linearize the wide-band power amplifier. | 11-26-2009 |
20090289707 | DISTORTION COMPENSATION APPARATUS AND METHOD - The distortion compensation apparatus includes: a branching unit to branch a part of the output signal of an amplifier to a signal path to a distortion compensating unit; a switch to pass the output signal of the amplifier to the interference or branching unit; and a controlling unit to control an amount of the compensation of the distortion under a pass-permitted state in which the switch passes the output signal in response to a result of measurement of a signal transmitted through the signal path under a state where the switch is in an interruption state. | 11-26-2009 |
20090289708 | Predictive feedback compensation for PWM switching amplifiers - Methods and systems are disclosed for predictive feedback compensation (PFC) circuitry for suppressing distortions caused by supply voltage variations and output amplitude switching non-idealities in pulse width modulated (PWM) switching amplifiers by pre-compensating the PWM input based upon the supply voltage or output pulse amplitude. Output amplitude errors associated with previous PWM output signals are used to predict output amplitude errors expected for future PWM output signals. These predicted output amplitude errors are then used to adjust the pulse widths for the future PWM output signals. Traditional feedback techniques can also be used in conjunction with the predictive feedback compensation (PFC) circuitry. | 11-26-2009 |
20090302939 | POWER AMPLIFIER WITH DIGITAL PRE-DISTORTION - A power amplifier using a digitally pre-distorted compound semiconductor transistor is discussed. The amplifier has improved linearity. For a given gate bias voltage, there exists a drain voltage at which the drain current is the same for a pulsed signal as for a DC signal and is invariant to quiescent bias points occurring when a pulsed signal is applied. If an amplifier operates at this point, the trapping effects that lead to memory effects do not affect the dynamic behaviour of a digitally pre-distorted amplifier, resulting in improved linearity. The existence of this point, and it's benefits to the linearity of a digitally pre-distorted amplifier, have not been previously recognised. | 12-10-2009 |
20090302940 | PREDISTORTION WITH SECTIONED BASIS FUNCTIONS - A predistortion actuator is provided. The predistortion actuator includes a plurality of branches, each of which implements a basis function that acts on a digital input signal. For at least one of the branches, the respective basis function is a sectioned basis function, where each section of the sectioned basis function corresponds to a respective section of a range of at least one input signal characteristic associated with the digital input signal, such as a value range of a magnitude, a temporal characteristic, or a hybrid of the two. A power amplifier system including the predistortion actuator is also provided. Utilizing sectioned basis functions can potentially reduce the hardware resources necessary to realize the predistortion actuator relative to conventional global basis functions. In addition, signal conditioning during coefficient training can potentially be used to reduce the dynamic range of coefficients associated with each sectioned basis function. | 12-10-2009 |
20090309657 | Predistortion Apparatus, System, And Method - The present invention discloses a predistortion apparatus, a predistortion system and a predistortion method. The predistorter comprises a modular value calculating section, for performing modular arithmetic on an information source input signal inputted from an information source; an orthogonal lookup table value acquiring section, for searching N stored lookup tables orthogonal to one another, finding out corresponding output of each lookup table in accordance with the modular value of the information source input signal, and acquiring N lookup table values, wherein N is an integer greater than 1; a multiplying section, for multiplying the N lookup table values acquired by the orthogonal lookup table value acquiring section with N amplitude adjustment factors to obtain N amplitude adjustment values, and multiplying the N lookup table values with N phase adjustment factors to obtain N phase adjustment values; and a summating section, for summating the N amplitude adjustment values to obtain an amplitude predistortion value, and summating the N phase adjustment values to obtain a phase predistortion value. | 12-17-2009 |
20090322424 | POWER AMPLIFIER WITH PRE-DISTORTER - Amplifier apparatus comprising a power amplifier having an operating frequency in the radio frequency or microwave or higher ranges and a pre-distorter, the characteristics of the power amplifier comprising a distortion from a linear transfer function. The pre-distorter comprises a non-linear path and a linear path including amplifiers having substantially identical physical characteristics, an input divider responsive to an amplifier input signal for applying respective pre-distorter input signals to the paths, and an output coupler for combining the signals from the linear path and the non-linear path to produce a pre-distorted signal. The characteristics of the pre-distorter comprise a distortion relative to a linear transfer function that compensates for the distortion of the transfer function of the power amplifier. | 12-31-2009 |
20090322425 | Distortion Compensating Amplifier And Front-End Distortion Compensation Amplifying Device - A distortion compensating amplifier including a forward circuit and a feedback circuit and performing distortion compensation of a signal in the forward circuit by use of a gain of the feedback circuit, includes a detecting unit which detects that the gain of the forward circuit is changed, a calculating unit which calculates, when the detecting unit detects that the gain of the forward circuit is changed, the gain of the feedback circuit on the basis of an input signal to the forward circuit and an output signal from the forward circuit, and a feedback gain updating unit which updates the present gain of the feedback circuit with the gain calculated by the calculating unit. | 12-31-2009 |
20100001795 | Baseband Predistortion Device And Method - The present invention discloses a baseband predistorter and baseband predistortion method. The baseband predistorter comprising: an address generator for calculating an address of a phase basic lookup table and an address of an amplitude basic lookup table; a parameter determining unit for determining a phase translational amount, an amplitude translational amount, a phase curvature adjustment amount and an amplitude curvature adjustment amount; a phase translating unit for changing the address in accordance with the phase translational amount; an amplitude translating unit for changing the address in accordance with the amplitude translational amount; a phase basic lookup table searching section for determining a corresponding phase output; an amplitude basic lookup table searching section, for determining a corresponding amplitude output; a phase curvature adjusting section, for adjusting the phase output; and an amplitude curvature adjusting section, for adjusting the amplitude output. | 01-07-2010 |
20100007415 | SIGNAL NONLINEAR DISTORATION MAGNITUDE DETECTION METHOD AND DEVICE - The present invention relates to a method for detecting signal nonlinear distortion magnitude, used for extracting and detecting the nonlinear distortion output by a radio frequency power amplifier, characterized in respectively extracting input signal and output signal, and performing square after matching the amplitudes and frequencies of the input signal and output signal respectively, obtaining respective low frequency components of the squared input signal and output signal, therefore, the carrier component of the signals can be filtered, and the low frequency components can characterize the distorted signal feature as well as facilitate handling. The present invention performs square after matching the input signal and output signal, extracts the low frequency component, and then the relativity with the frequency and bandwidth of the signal is low, therefore, the difficulty in detecting the distortion can be reduced greatly. In addition, the square is equivalent to amplify the distortion, which is favorable to improve the detection sensitivity of output distortion. | 01-14-2010 |
20100033246 | ADAPTIVE DIGITAL PREDISTORTION OF COMPLEX MODULATED WAVEFORM USING PEAK AND RMS VOLTAGE FEEDBACK FROM THE OUTPUT OF A POWER AMPLIFIER - Exemplary embodiments of the invention includes an amplifier and a processor that adapts a baseline or previous model of the input-output signal characteristic of the amplifier using metrics of the system, including peak power, peak voltage, average power, root mean square (RMS) voltage, samples of the output signal of the amplifier, or environmental metrics such as temperature, power supply voltage, signal frequency, etc. In particular, the system comprises an amplifier; a device to measure a metric of the system; a processor to generate a present model of the input-output signal characteristic of the amplifier based on the system metric; and a predistortion device to predistort the input signal for the amplifier based on the present amplifier model. | 02-11-2010 |
20100039174 | RF SYSTEM LINEARIZER USING CONTROLLED COMPLEX NONLINEAR DISTORTION GENERATORS - A linearizer reduces nonlinear intermodulation distortion in radio frequency and microwave systems by first directly generating in-phase and quadrature nonlinear intermodulation products of the system input. Controllable amounts of each phase are then added back into the system such that the vector sum of nonlinear intermodulation products at the output is reduced or eliminated by destructive interference, while the fundamentals are substantially unaffected. The quadrature distorted signals are generated with two lightly-biased and thus overdriven differential pairs having gain-determining degeneration impedances that are in quadrature with each other The amount of each quadrature phase summed to the output is controlled with electronically tunable four-quadrant variable attenuators. The quadrature phasing enables rapidly convergent tuning to minimize distortion using conventional scalar spectral analysis. The advantages of a linearizer using rectangular vector coordinate system are significant. | 02-18-2010 |
20100045375 | DEVICE FOR THE LOW-DISTORTION TRANSFORMATION, PARTICULARLY AMPLIFICATION OF SIGNALS - The invention describes a device for the low-distortion conversion, especially amplification, of signals. In one embodiment, the device comprises a digital-to-analog converter having adjustable reference voltages to which an analog-to-digital converter having adjustable reference voltages may be connected upstream. In a further embodiment, the device has a unit, which predistorts a digitized signal, or a digital signal, corresponding to the characteristic transfer line of the amplifier. In a further embodiment, the device has a unit, which equalizes a distorted digitized signal corresponding to the characteristic transfer line of the amplifier stored in the unit. In yet a further embodiment, the device has a digital-to-analog converter operating on the basis of the summation of weighted currents. | 02-25-2010 |
20100052780 | METHOD OF AND CIRCUIT FOR REDUCING DISTORTION IN A POWER AMPLIFIER - An integrated circuit having a circuit for reducing distortion in a power amplifier is disclosed. The integrated circuit comprises a predistortion circuit coupled to receive a signal to be amplified; sample capture buffers coupled to an output of the predistortion circuit and an input/output port of the integrated circuit; and an estimator circuit coupled to the sample capture buffers, wherein the estimator circuit generates parameters for the predistortion circuit based upon the output of the predistortion circuit and an output of the power amplifier received at the input/output port of the integrated circuit. A method of reducing distortion in a power amplifier is also disclosed. | 03-04-2010 |
20100052781 | Correcting distortions at output of power amplifier - A solution is provided for correcting distortions on a radio frequency output signal of a power amplifier. There is provided an apparatus, comprising: a processor configured to determine at least one correction factor for a distortion on a radio frequency output signal of a power amplifier on the basis of estimated characteristics of a distorted time-varying supply voltage from a power supply to a power amplifier and an interface configured to feed the at least one correction factor to an input signal of the power amplifier. | 03-04-2010 |
20100060355 | APPARATUS AND METHOD OF COMPENSATING DISTORTION - A distortion compensating apparatus includes a processing circuit that calculates each of a plurality of series operation coefficient pairs based on a transmission signal and a feedback signal of an output from an amplifying circuit performing power amplification of the transmission signal, executes a series operation process with respect to the transmission signal based on the plurality of the series operation coefficient pairs as a distortion compensation of the transmission signal, and inputs a result of the series operation process to the amplifying circuit performing the power amplification, and a selecting unit that, on the basis of power of the transmission signal, selects the series operation process to be executed corresponding to one of the plurality of series operation coefficient pairs, or selects one of the plurality of series operation coefficient pairs to be used in the series operation process to be executed. | 03-11-2010 |
20100060356 | POWER SERIES PREDISTORTER AND CONTROL METHOD THEREOF - A power series predistorter of the present invention includes a delay path for delaying a signal, a distortion generation path having an N-th order distortion generator and a vector adjuster, a divider for dividing an input signal between the delay path and the distortion generation path, a combiner for combining the output signal of the delay path and the output signal of the distortion generation path, and a controller for controlling the vector adjuster. The controller includes a setting unit, a distortion component measurement unit, a minimum condition calculation unit, and a recording unit. The setting unit specifies the phase or amplitude value of the vector adjuster. The distortion component measurement unit measures the distortion component of a power amplifier. The minimum condition calculation unit obtains a phase or amplitude value that minimizes the distortion component by function approximation, using the magnitude of the distortion components corresponding to three or more phase or amplitude values specified for sampling by the setting unit. | 03-11-2010 |
20100066445 | POWER AMPLIFIER, METHOD FOR CONTROLLING POWER AMPLIFIER, AND WIRELESS COMMUNICATION APPARATUS - A power amplifier includes: a distortion compensating circuit that causes a bias circuit to have an output impedance so that a subsequent block bipolar transistor for signal amplification-use has a maximized saturated output power; and a distortion compensating circuit that causes a bias circuit to have an output impedance so that a distortion of an output power of the power amplifier | 03-18-2010 |
20100073086 | Method and apparatus for producing linearized optical signals - A method for producing an optical output in substantially linear relationship with an electrical AC signal, includes the following steps: providing a light-emitting transistor having emitter, base, and collector regions, and associated respective emitter, base, and collector terminals, the transistor having a light-emitting output port; applying the AC signal to a first input port defined across a given one of the terminals and a common one of the terminals; applying an amplified version of the AC signal to a second input port defined across a further one of the terminals and the common one of the input terminals; and selecting an amplification of the amplified version of the AC signal to substantially cancel a nonlinearity characteristic of the light emitting transistor. | 03-25-2010 |
20100079206 | Digital Adaptive Feedforward Harmonic Distortion Compensation for Digitally Controlled Power Stage - Systems and method to compress digital video based on human factors expressed as a desirability score are provided. A particular method includes passing a digital input signal through a pulse-width modulator and passing an output of the pulse-width modulator through a power switching device. An output of the power switching device has a plurality of pulses. The method includes receiving the output of the power switching device at a first input of a comparator and receiving a reference voltage at a second input of the comparator. The method includes determining a net signal based on an output of the comparator and determining a timing error signal based on the net signal and the digital input signal. The method also includes adjusting the digital input signal to compensate for harmonic distortion based at least in part on the timing error signal. | 04-01-2010 |
20100085117 | APPARATUS FOR PROCESSING AN AUDIO SIGNAL AND METHOD THEREOF - An apparatus for processing an audio signal and method thereof are disclosed, by which a local dynamic range of an audio signal can be adaptively normalized as well as a maximum dynamic range of the audio signal. The present invention includes receiving, by an audio processing apparatus, a signal, and feedback information estimated based on a normalizing gain; generating a noise estimation based on the signal; computing a gain filter for noise canceling, based on the noise estimation and the signal; and, obtaining a restricted gain filter by applying the feedback information to the gain filter. | 04-08-2010 |
20100097137 | LOOKUP TABLE GENERATION METHOD AND RELATED DEVICE FOR A PREDISTORTER - A lookup table generation method for a predistorter comprises sending a first single tone signal with a maximum expected amplitude to a channel simulation device including the power amplifier, estimating a closed loop gain and a closed loop phase of the power amplifier according to the first single tone signal and a first simulation output signal generated outputted by the channel simulation device, sending a plurality of single tone signals to the channel simulation device, each single tone signal having an amplitude different from all others of the plurality of single tone signals and lower than the maximum expected amplitude, generating a plurality of predistortion parameters according to the closed loop gain, the closed loop phase, the plurality of single tone signals and a plurality of simulation output signals outputted by the channel simulation device, and storing the plurality of predistortion parameters in a lookup table of the predistorter. | 04-22-2010 |
20100097138 | RF Power Transmission, Modulation, and Amplification Embodiments - Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion. | 04-22-2010 |
20100109771 | REPEATING SYSTEM AND METHOD FOR CANCELLATION OF FEEDBACK INTERFERENCE SIGNAL WITH PRE-DISTORTION FUNCTION - There is provided a repeating system for cancellation of a feedback interference signal, including: a PA (Power Amplifier) for power-amplifying an output signal; a feedback ICS (Interference Cancellation System) for canceling a feedback interference signal and detecting a residual error; a pre-distorter for compensating for an error of the PA by applying pre-distortion and compensating for the residual error by using information on the residual error detected by the feedback ICS to linearize the characteristic of the PA; and a control unit for controlling the feedback ICS and the pre-distorter. | 05-06-2010 |
20100117729 | Distortion Compensation Apparatus And Method - A distortion compensation apparatus having a circuit configured to perform power amplification of a transmission signal; and a circuit configured to feedback the transmission signal output from the circuit configured to perform power amplification and obtain a demodulated signal of the transmission signal, while calculating and holding a distortion compensation coefficient with which an error between the demodulated signal and the transmission signal before the power amplification becomes minimum, to perform distortion compensation of the transmission signal based on the distortion compensation coefficient and provide the compensated transmission signal to the circuit configured to perform the power amplification, the distortion compensation apparatus includes: a gain adjustment unit to adjust a gain of the transmission signal; and a gain control unit to adaptively adjust a gain of the gain adjustment unit based on the held distortion compensation coefficient. | 05-13-2010 |
20100123519 | APPARATUS AND METHOD FOR CONTROLLING DISTORTIONS OF AMPLIFIER - Disclosed are an apparatus and method for controlling output distortions of an amplifier. The apparatus for controlling output distortions of an amplifier, includes a compensation signal generator to predict a fluctuation of a supply voltage of a power supply using a prediction model which reflects fluctuations characteristics of the supply voltage, and to generate a compensation signal based on the prediction, and a compensator to transform an input signal using the compensating signal to control the output distortions. | 05-20-2010 |
20100127774 | DISTORTION CORRECTION DEVICE AND METHOD FOR POWER AMPLIFIER - A distortion correction device and method for power amplifier are provided. The power amplifier receives an input signal and generates a first output signal. The distortion correction device includes a self-mixing mixer and an adaptive calculator. The method includes steps of: utilizing the self-mixing mixer to receive the first output signal and generate a second output signal based on the first output signal, wherein the second output signal includes a plurality of baseband components corresponding to signal spectrum of the input signal; and utilizing the adaptive calculator to perform an adaptation algorithm to generate a look-up table based on the baseband components. | 05-27-2010 |
20100141339 | Apparatus and Method for Broadband Amplifier Linearization - An apparatus and method to improve broadband amplifier linearization. The present circuits make use of pre-distortion techniques to improve the 3 | 06-10-2010 |
20100148865 | METHOD AND SYSTEM FOR CALCULATING THE PRE-INVERSE OF A NONLINEAR SYSTEM - An apparatus is provided to determine pre-distortion for a nonlinear system. The apparatus comprises a datapath and a power amplifier. The datapath employs predistortion data to generally linearized the power amplifier. To generate this predistortion data, an indirect learning circuit and a direct learning circuit can be employed. The indirect learning circuit is generally coupled to the amplifier circuit so that it can iteratively adjust predistortion data during an indirect learning mode until convergence is reached. The direct learning circuit is generally coupled to the amplifier circuit and the indirect learning circuit and that receives the input signal so that the predistortion data can be copied to the direct learning circuit from the indirect learning after convergence is reached and so that the direct learning circuit can adjust the predistortion data during a direct learning mode. | 06-17-2010 |
20100156529 | APPARATUS AND METHOD FOR ESTIMATING POWER FOR AMPLIFIER - Described herein is an apparatus and method for estimating the amount of power that is to be consumed by an amplifier. An estimation section may be determined based on frame data of an input signal that is to be input to the amplifier. The estimation section may be stored to in a predetermined section, and the amount of power to be consumed by the amplifier may be estimated in advance based on the stored signal. The predetermined section may be determined in consideration of response a characteristic of a power supply of the amplifier. The amount of power may be calculated by assigning weight to the stored signal. | 06-24-2010 |
20100156530 | DISTORTION COMPENSATION APPARATUS AND METHOD - A distortion compensation apparatus includes a distortion compensation unit that performs distortion compensation processing on a transmission signal by a series operation, a coefficient update unit that updates a group of series operation coefficients used for the series operation based on a feedback signal of transmission signal output that is output after power amplification processing is performed on output of the distortion compensation unit and the transmission signal, an initial coefficient memory that stores the groups of series operation coefficients that become initial values for coefficient update processing by the coefficient update unit, and a power fluctuation detection unit that detects a power fluctuation of the transmission signal and, when the power fluctuation is detected, reads the groups of series operation coefficients from the initial coefficient memory and provides the groups of series operation coefficients to the coefficient update unit. | 06-24-2010 |
20100164620 | PREDISTORTION APPARATUS AND PREDISTORTION METHOD - A predistortion apparatus for compensating for a distortion arising from a non linear property in input to output characteristics of an amplifier, by processing calculation of a plurality of coefficients for a plurality of power series defining the predistortion characteristics for a plurality of power ranges, respectively, the predistortion apparatus includes: a coefficient update unit for setting and updating coefficients of the power series to provide the predistortion characteristics for the plurality of power ranges in accordance with a comparison between the input and output of the amplifier; and a determination unit for determining at least one threshold value defining the plurality of power ranges by shifting the threshold value and operating the coefficient update unit for updating the coefficients for each of the power series corresponding to each of the power ranges defined by the shifted threshold value. | 07-01-2010 |
20100182081 | Feedforward distortion compensation amplifier - A feedforward distortion compensation amplifier includes an adjusting unit for adjusting a gain and a phase of an input signal, a first amplifier for amplifying a signal outputted from the adjusting unit, a delay unit for delaying the input signal, and a coupler for coupling a signal outputted from the delay unit to a signal outputted from the first amplifier. The feedforward distortion compensation amplifier further includes a first controller which detects a distortion component of the first amplifier to control an operation of the adjusting unit based on the distortion component, and a second controller which determines one distortion level from distortion levels based on a magnitude of the input signal, and compares the determined distortion level with the detected distortion component of the first amplifier to control an amplification rate of the first amplifier based on comparison results. | 07-22-2010 |
20100188148 | PREDISTORTION MECHANISM FOR COMPENSATION OF TRANSISTOR SIZE MISMATCH IN A DIGITAL POWER AMPLIFIER - A novel and useful apparatus for and method of predistortion compensation of device (e.g., transistor) mismatch in a digital power amplifier (DPA). The device mismatch predistortion mechanism of the present invention addresses the problem of matching between two types of binary weighted transistors, whereby mismatched transistors cause degradation in wideband noise. The invention provides a digital predistortion mechanism which functions to pre-distort the mismatch ratio based on a data table calculated a priori enabling a polar transmitter to meet output spectrum and error vector magnitude (EVM) requirements of the particular modern wideband wireless standard, such as GSM, 3G WCDMA, etc. | 07-29-2010 |
20100188149 | Lock-in Amplifier and Method for Filtering a Measurement Signal Using Such an Amplifier - A lock-in amplifier with an additional phase-sensitive detector is provided. A measurement signal is mixed in a multiplicative fashion with a reference signal, which is phase-shifted by 90 degrees, for a modulation frequency. In order to reliably filter out interference signal portions in a widest possible dynamic range and, at the same time, minimize unavoidable influence on the useful signal portion, a control device is connected downstream of the additional phase-sensitive detector. The control device determines a control variable corresponding to the strength of the interference signal from the measurement signal mixed with the reference signal phase shifted by 90 degrees and uses the control variable to change the integration duration of the integrator proportionally to the control variable, a corresponding cut-off frequency of an equivalent low pass being coordinated automatically. | 07-29-2010 |
20100194474 | Predistorter and Distortion Compensation Method - A predistorter includes a distortion compensating unit which gives, in advance, a reverse characteristic of a characteristic of input to output of a power amplifier to a transmission signal which is to be input to the power amplifier; a distortion compensation signal generating unit which generates a distortion compensation signal indicating the reverse characteristic based on transmission data that is sample data of the transmission signal and the delayed transmission data; and a delay amount control unit which controls a delay amount of the transmission data according to an output signal of the power amplifier. | 08-05-2010 |
20100201442 | DISTORTION COMPENSATION DEVICE FOR USE IN HIGH-FREQUENCY POWER AMPLIFIER - A non-linear distortion signal contained in output signal components from a high-frequency power amplifier is detected, while a non-linear distortion signal is generated from a high-frequency signal to be amplified. Correlation between this non-linear distortion signal and the detected non-linear distortion signal is determined, and a control variable is calculated based on the signal thus obtained. The obtained control variable is multiplied by the generated non-linear distortion signal to generate a distortion compensation signal, which is added to the signal to be amplified. This provides a distortion compensation device capable of automatically maintaining optimum distortion compensation characteristics and rapidly achieving desirable distortion compensation. | 08-12-2010 |
20100214018 | ADAPTIVE PREDISTORTION FOR A TRANSMIT SYSTEM - Systems, methods, and devices relating to the provision of deliberate predistortion to an input signal to compensate for distortions introduced by an amplifier subsystem. An input signal is received by a signal processing system which includes a predistortion subsystem. The input signal is decomposed and the fragments are then predistorted by the predistortion subsystem by applying a deliberate predistortion to the fragments. The predistorted fragments are then separately processed and recombined to arrive at the system output signal. The predistortion subsystem adaptively adjusts based on characteristics of the system output signal. Also, the predistortion subsystem is equipped with a control system that is state based—the state of the predistortion subsystem is dependent upon the prevailing conditions and, when required, the control system switches the state of the predistortion subsystem. A feedback signal, a replica of the system output signal, is used in updating lookup table entries used to determine the predistortion. | 08-26-2010 |
20100219889 | DISTORTION COMPENSATION APPARATUS AND METHOD - A distortion compensation apparatus includes a distortion compensation signal generation unit that performs, on a transmission signal, distortion compensation processing using a series operation; a coefficient updating unit that updates series operation coefficients used for the series operation based on a feedback signal of a power amplification output which is output through power amplification processing of a distortion compensation signal output from the distortion compensation signal generation unit, and based on the distortion compensation signal; a memory that stores the distortion compensation signal corresponding to a transmission signal having a given power value and the feedback signal of the power amplification output as restraint information; and a control unit that performs control so that, in accordance with the power value of the transmission signal, restraint information corresponding to a power value different from the power value of the transmission signal is read and used for updating the series operation coefficients. | 09-02-2010 |
20100225389 | HIGH EFFICIENCY RF SYSTEM LINEARIZER USING CONTROLLED COMPLEX NONLINEAR DISTORTION GENERATORS - A linearizer reduces nonlinear intermodulation distortion in radio frequency and microwave systems by first directly generating in-phase and quadrature nonlinear intermodulation products of the system input. Controllable amounts of each phase are then added back into the system such that the vector sum of nonlinear intermodulation products at the output is reduced or eliminated by destructive interference, while the fundamentals are substantially unaffected. The quadrature distorted signals are generated with two lightly-biased and thus overdriven differential pairs having gain-determining degeneration impedances that are in quadrature with each other. The amount of each quadrature phase summed to the output is controlled with electronically tunable four-quadrant variable attenuators. The quadrature phasing enables rapidly convergent tuning to minimize distortion using conventional scalar spectral analysis. The advantages of a linearizer using rectangular vector coordinate system are significant. | 09-09-2010 |
20100225390 | Resource Efficient Adaptive Digital Pre-Distortion System - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 09-09-2010 |
20100237937 | POWER AMPLIFYING DEVICE AND POWER AMPLIFYING METHOD - A power amplifying device includes an amplifier that amplifies a signal which is input in accordance with a voltage signal which is supplied to the amplifier, a voltage control section that controls the voltage signal in accordance with a transmission signal, a distortion compensating section that executes a distortion compensating process on the transmission signal by giving a value indicative of a reverse characteristic of the amplifier to the transmission signal in advance and inputs an output signal obtained by executing the distortion compensating process into the amplifier, an amplitude detecting section that detects an amplitude of the transmission signal, and a timing adjusting section that adjusts timings of the output signal and the voltage signal so that a value relating to the distortion compensating process meets a given condition when a detected value of the amplitude of the transmission signal is less than a given value. | 09-23-2010 |
20100244953 | CDMA/OFDM Compliant Wireless Communication from a Non-Linear Finite Impulse Response Filter Configured with Coefficients that are Responsive to an Input Signal Magnitude - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 09-30-2010 |
20100244954 | CDMA/OFDM Linearity Compliant Wireless Communication Amplifier - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 09-30-2010 |
20100253425 | METHOD AND APPARATUS FOR PERFORMING PREDISTORTION - Embodiments are described herein to provide better predistortion solutions for the linearization of high power amplifiers, especially those with memory effects. Many embodiments involve a method in which a predistorted signal z | 10-07-2010 |
20100253426 | High-Efficiency Power Amplifier - A high-efficiency power amplifier is provided, including a drive amplifier and a final power amplifier, and further including a first digital pre-distortion (DPD) correction module and a second DPD correction module. The first DPD correction module is configured to pre-distort nonlinear characteristics of drive signals output by the drive amplifier, and the second DPD correction module is connected to the first DPD correction module in series, and is configured to pre-distort nonlinear characteristics of amplified signals output by the final power amplifier. Another high-efficiency power amplifier is also provided, including a drive amplifier and a final power amplifier, and further including a second multi-path control module, a fourth DPD correction module, and a second gating module. The overall efficiency of the high-efficiency power amplifier is increased by improving the working efficiency of the drive amplifier. Further, higher overall efficiency is also achieved for a power amplifier with a higher gain. | 10-07-2010 |
20100271123 | ADAPTIVE DIGITAL PREDISTORTION OF COMPLEX MODULATED WAVEFORM USING LOCALIZED PEAK FEEDBACK FROM THE OUTPUT OF A POWER AMPLIFIER - Exemplary embodiments of the invention includes an amplifier and a processor that adapts a baseline or previous model of the input-output signal characteristic of the amplifier using metrics of the system, including peak power, peak voltage, average power, root mean square (RMS) voltage, samples of the output signal of the amplifier, etc. In particular, the system comprises an amplifier; a device to measure a metric of the system; a processor to generate a present model of the input-output signal characteristic of the amplifier based on the system metric as determined through a localized sampling window of the output signal; and a predistortion device to predistort the input signal for the amplifier based on the present amplifier model. | 10-28-2010 |
20100271124 | Distortion Compensation Device - A distortion in an amplified signal obtained by amplifying a first input signal, is compensated for by applying a correction factor to the first input signal. The correction factor is updated based on the first input signal and the amplified signal. Updating the correction factor is prohibited when a value of the first input signal is same as a value of a second input signal among a plurality of input signals input previous to the first input signal. | 10-28-2010 |
20100271125 | DISTORTION COMPENSATION APPARATUS AND METHOD FOR DETECTING FAILURE IN THE SAME - There is provided a distortion compensation apparatus for compensating distortion of an output of a power amplifier included in a radio transmitter. The distortion compensation apparatus includes a difference value calculator to calculate a difference value between a reference signal and a feedback signal, where the reference signal is branched from an input signal to the power amplifier and the feedback signal is branched from an output from the power amplifier; an integrator to accumulate the difference value; and a failure determiner to determine based on the accumulated difference value whether or not a failure has occurred or not. | 10-28-2010 |
20100277236 | PREDISTORTER - Provided is a predistorter which compensates for a memory effect occurring in an amplifier used in a communication device, especially an electric memory effect as well. The predistorter includes: a distortion compensation circuit ( | 11-04-2010 |
20100283540 | Pre-distortion for a Radio Frequency Power Amplifier - Coefficients of a pre-distorter are determined for correction of distortion of a signal amplified by a radio frequency amplifier by sampling the signal at the input to the pre-distorter to generate a plurality of input samples and sampling the signal at the output of the amplifier to generate a plurality of output samples, each of the plurality of output samples corresponding to one of the plurality of input samples, calculating a figure of merit for one or more of said plurality of input samples on the basis of the one or more of said plurality of input samples, selectively updating a previously selected set of input samples with said one or more of said plurality of input samples on the basis of the calculated figure of merit, whereby to generate an updated selected set and determining the coefficients of the pre-distorter on the basis of the input samples in the updated selected set and the corresponding output samples. | 11-11-2010 |
20100289572 | PREDISTORTER, PREDISTORTION METHOD, AND PREDISTORTION SYSTEM - This invention relates to a predistorter, a predistortion method, and a predistortion system. The predistorter comprises a modulus value determining section, for determining a modulus value of an input signal; a base searching section, for searching a predetermined base lookup table in accordance with the modulus value of the input signal, so as to obtain a base lookup table value; an offset searching section, for searching a predetermined offset lookup table in accordance with the modulus value of the input signal, so as to obtain an offset lookup table value; an interpolation factor generating section, for generating an interpolation factor in accordance with the modulus value of the input signal; a multiplying section, for multiplying the offset lookup table value with the interpolation factor; and a summating section, for adding a product obtained by the multiplying section to the base lookup table value, so as to obtain a predistortion value. | 11-18-2010 |
20100289573 | Distributed Mobile Communication Network - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 11-18-2010 |
20100289574 | Signal Pre-Distortion Facility for Amplifier Non-Linearity Compensation - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 11-18-2010 |
20100289575 | Increasing the Density of Larger Magnitude Amplifier Output Samples for Estimating a Model of Digital Pre-Distortion to Compensate for Amplifier Non-Linearity - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 11-18-2010 |
20100295611 | DISTORTION COMPENSATION APPARATUS - An apparatus for compensating a distortion characteristic of an amplifier includes an update unit configured to store a distortion compensation coefficient, configured to calculate the coefficient based on a signal before input to the amplifier and a feedback signal, and configured to update the stored coefficient to the calculated coefficient; a distortion compensation unit configured to perform distortion compensation processing of the signal before input to the amplifier by using the updated coefficient; a delay unit configured to delay the signal before input to the amplifier by a set delay time, to output the delayed signal to the distortion compensation coefficient update unit; and a delay controller configured to control the set delay time based on a phase of a complex number having a power component of the signal before input to the amplifier as a real part, and a power component of the feedback signal as an imaginary part. | 11-25-2010 |
20100295612 | POWER SERIES DIGITAL PREDISTORTER AND CONTROL METHOD THEREFOR - A power series digital predistorter includes a combiner which combines an output from a linear transmission path with an output from an odd-order distortion generating path, an analog-to-digital converter which converts a feedback signal from an output of a power amplifier to a digital feedback signal, an odd-order distortion vector control part which controls vector adjustment performed by an odd-order distortion vector adjusting part in the odd-order distortion generating path, a cancellation signal generating part which generates a cancellation signal from an input transmission signal, a combiner which is inserted in a feedback signal path and which combines the cancellation signal with a signal from the feedback signal path, and a cancellation signal control part which controls the cancellation signal generating part so that the cancellation signal suppresses a main signal component in the feedback signal at the combiner. | 11-25-2010 |
20100295613 | SUPPLY-MODULATED RF POWER AMPLIFIER AND RF AMPLIFICATION METHODS - An embodiment of the invention is a method of generating a reduced bandwidth envelope signal V | 11-25-2010 |
20100301936 | DIFFERENTIAL LOW FREQUENCY NOISE SUPPRESSION TECHNIQUE FOR A COMMON MODE FEEDBACK CIRCUIT - Disclosed is a common mode feedback circuit for a differential amplifier that eliminates the effects of low frequency noise. A modulator is placed in a common mode feedback loop that modulates the feedback loop signal at a predetermined frequency to up-convert the low frequency noise. The predetermined frequency may be selected to be above the operating range of the downstream circuitry. In addition, a low pass filter can be used to eliminate the up-converted noise. | 12-02-2010 |
20100308910 | APPARATUS AND METHOD FOR PREDICTIVE OVER-DRIVE DETECTION - A method and apparatus for efficient drive level selection for, e.g., power amplifiers utilized within a wireless communication system, which utilizes digital predistortion (DPD) to adaptively and predictively select drive level. The DPD, e.g., increases the power amplifier's efficiency while maintaining spectral mask compliance within the designated frequency band of transmission. The method first determines a peak amplitude of an undistorted waveform that is to be transmitted and then predicts the maximum power that is to be transmitted by the power amplifier after the undistorted signal has been predistorted. An over-drive metric is then calculated based upon the predicted drive level of the power amplifier, which indicates whether or not the cascade of the predistorter and the power amplifier is predicted to operate linearly. The over-drive metric may then be used to ensure optimal power amplifier performance, thereby eliminating the need to use overly conservative power amplifier drive settings. | 12-09-2010 |
20100327971 | Transmission device, distortion compensation device, and distortion compensation method - A transmission device includes an amplifier that amplifies a transmission signal according to a voltage to be applied, an envelope detector that detects an envelope signal of the transmission signal, a rate decreasing unit that decreases changing rate of the envelope signal detected by the envelope detector, and a voltage controller that changes the voltage applied to the amplifier according to the envelope signal whose changing rate is decreased by the rate decreasing unit. | 12-30-2010 |
20110025413 | Dynamic Radio Frequency Amplifier Distortion Adjustment Based on Linearly Interpolating from a Sample of Pre-Distortion Coefficients that are Selected Based on Signal Magnitude - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 02-03-2011 |
20110025414 | PREDISTORTION OF AMPLIFIER INPUT SIGNALS - Described herein are devices, methods, and techniques related to predistortion of amplifier signals based on an operating condition. Predistortion techniques are described that mitigate or eliminate the effects of variable operating conditions, including nonlinear effects, on amplified signals. Nonlinearities may be mitigated by compensating at a baseband signal prior to amplification, generally using scaling and a static characteristic that is valid for a broad range of operating conditions. | 02-03-2011 |
20110032032 | DIGITAL PREDISTORTER FOR VARIABLE SUPPLY AMPLIFIER - An adaptive predistorter for applying a predistortion gain to an input signal to be amplified by a power amplifier having a variable supply voltage, the predistorter including: a predistortion gain block adapted to apply a complex gain to a complex input signal; a first table implemented in a first memory and comprising a 2-dimensional array of cells storing complex gain values, the first table adapted to output the complex gain values based on an amplitude of the input signal and the value of the variable supply voltage of the power amplifier; and a second table implemented in a second memory and including a 2-dimensional array of cells storing gain update values for updating the complex gain values of the first table, the gain update values being generated based on an output signal of said power amplifier. | 02-10-2011 |
20110032033 | PRE-DISTORTION AND MEMORY COMPENSATION APPARATUS - Pre-distortion and memory compensation apparatuses and methods for a non-linear component are provided. The apparatus comprises an adaptive block for generating a plurality of correlation coefficients, which are used to weight a plurality of synthesis work functions to pre-distort a given signal. The adaptive block can be driven by an error signal generated from a feedback signal from the non-linear component output signal and a delayed version of the input signal. The apparatus is capable of being operated directly at radio frequency. Also provided are apparatuses and methods for generation of quadrature signals, transconductance amplification employing negative resistance, variable-gain amplification, and envelope detection. | 02-10-2011 |
20110050338 | Modulated Triangular Wave Amplifier - The invention is a power amplifier circuit for providing a signal acceptable for use in audio amplifiers or similar applications without requiring a stable power supply free from fluctuations. An alternating current power supply signal rectified to a direct current signal is processed by two voltage multipliers. A voltage divider establishes a unity gain level, and the variance from this voltage is squared by the first voltage multiplier. This squared voltage is then multiplied with a triangular wave signal to generate a modulated triangular wave signal. The modulated triangular wave signal and a signal to be amplified, typically an audio signal, are processed by an internal comparator to generate a pulse width modulated signal. This modulated signal is processed by a power transistor network and filter to provide an amplified signal to a load device. By modulating the triangle wave signal to compensate for fluctuations in the power supply to the amplifier circuit, noise or ripples present in the power supply are demodulated, eliminating the requirement for a regulated power supply. | 03-03-2011 |
20110050339 | POWER SERIES DIGITAL PREDISTORTER AND DISTORTION COMPENSATION CONTROL METHOD THEREFOR - A power series digital predistorter and a distortion compensation control method for the power series digital predistorter are capable of adjusting the coefficients of a frequency characteristic compensator at high speed. A controller in the power series digital predistorter collectively sets adjustment amounts for the phases in bands in an N-th order frequency characteristic compensator; collectively sets adjustment amounts for the amplitudes in the bands in the N-th order frequency characteristic compensator; determines whether an index indicating the degree of cancellation of a distortion component generated in a power amplifier satisfies a preset condition; and, if the index does not satisfy the condition, performs control such that the adjustment amounts for the phases and the adjustment amounts for the amplitudes are set again. | 03-03-2011 |
20110063026 | PRE-DISTORTION APPARATUS OF POWER AMPLIFIER AND METHOD THEREOF - A pre-distortion apparatus of a power amplifier includes: a pre-distortion unit configured to generate a pre-distorted signal of an input signal by calculating a magnitude of the input signal and outputting a complex correction coefficient corresponding to the calculated magnitude of the input signal, and provide the generated pre-distorted signal as an input of the power amplifier; and a complex correct coefficient update unit configured to generate an error signal by comparing an output signal of the power amplifier with the input signal and updating the complex correction coefficient to minimize a magnitude of the generated error signal, wherein the pre-distortion unit provides a constant bias value corresponding to the magnitude of the input signal as a bias of the power amplifier while updating the complex correction coefficient. | 03-17-2011 |
20110068868 | Amplifier Device and Predistortion Control Method - This invention relates to an amplifier device and a predistortion control method. The amplifier device comprises a predistortion unit, a predistortion control unit, and an amplifier unit, of which the predistortion control unit controls the predistortion unit in accordance with a signal fed back from the amplifier unit. The predistortion control method comprises determining power of a left side lobe of two side lobes of a frequency spectrum of the signal fed back from the amplifier unit; determining power of a right side lobe of two side lobes of a frequency spectrum of the signal fed back from the amplifier unit; determining a cost function in accordance with the power of the first and right side lobes, and controlling the predistortion unit in accordance with the cost function. | 03-24-2011 |
20110074506 | CANCELLING NON-LINEAR POWER AMPLIFIER INDUCED DISTORTION FROM A RECEIVED SIGNAL BY MOVING INCORRECTLY ESTIMATED CONSTELLATION POINTS - A method and system are provided for reducing power amplifier induced distortion. Power amplifier induced distortion is iteratively estimated and cancelled. When the difference between the current estimated power amplifier distortion and the previous estimated power amplifier distortion is less than a convergence threshold, particular M-QAM constellation points that are still in error are determined A M-QAM constellation point correction routine is provided that can move the incorrectly estimated M-QAM constellation points that are in error towards their expected quadrants by generating updated M-QAM constellation points. The remaining estimated non-linear power amplifier induced distortion in the received signal can then be estimated and canceled. | 03-31-2011 |
20110080216 | Systems and Methods of Power Amplifier Digital Pre-Distortion - Systems and methods for power amplifier pre-distortion are provided. The systems and methods of power amplifier digital pre-distortion disclosed herein may include a generic pre-distorter architecture which can implement a variety of Volterra cross terms involving single dimension convolutions (first order dynamics). For hardware implementations, this generic pre-distorter is further fine-tuned to provide a choice between different sets of cross terms that can be selected for a given PA for optimal performance. The novel pre-distorter architecture provides flexibility to trade off memory depth for additional Volterra terms and vice versa. A further novelty is the ability to trade off both memory depth and cross terms for a higher sample rate operation, which may enable higher order non-linear pre-distortion, or support for higher signal bandwidths. A poly-phase non-linear filtering mode allows for this flexibility. | 04-07-2011 |
20110095819 | AMPLIFIER LINEARIZER - The present invention provides an advanced adaptive predistortion linearization technique to dramatically reduce nonlinear distortion in power amplifiers over a very wide instantaneous bandwidth (up to 2 GHz) and over a wide range of amplifier types, input frequencies, signal types, amplitudes, temperature, and other environmental and signal conditions. In an embodiment of the invention, the predistortion linearization circuitry comprises (1) a higher-order polynomial model of an amplifier's gain and phase characteristics—higher than a third-order polynomial model; (2) an adaptive calibration technique; and (3) a heuristic calibration technique. The higher-order polynomial model is generated by introducing, for example, a plurality of multi-tone test signals with varying center frequency and spacing into the power amplifier. From the power amplifier's corresponding output, the nonlinearities are modeled by employing a higher-order curve fit to capture the irregularities in the nonlinear transfer function. Different distortion transfer functions can be implemented for different operating conditions. The adaptive calibration technique is based on a feedback analysis technique, which updates the applicable distortion transfer function by analyzing the error signal between the introduced input signal and the output signal in real-time. The heuristic calibration technique implements different distortion transfer functions based on historical operating conditions and optimal configurations of the power amplifier. | 04-28-2011 |
20110095820 | METHOD FOR PRE-DISTORTING A POWER AMPLIFIER AND THE CIRCUIT THEREOF - A method for pre-distorting a power amplifier comprises the steps of: inputting a baseband digital training signal with time-varying amplitude into a transmitting end in a single operation; converting the baseband digital training signal to a radio-frequency analog training signal, and converting the radio-frequency analog training signal to a radio-frequency analog transmitting signal via a power amplifier; receiving the radio-frequency analog transmitting signal at a receiving end, and converting the received signal to a baseband digital receiving signal; and calculating parameters for pre-distorting the power amplifier by estimating the characteristic curve of the power amplifier according to the baseband digital receiving signal. | 04-28-2011 |
20110095821 | PRE-DISTORTION METHOD AND DEVICE TO ENHANCE THE POWER UTILITY OF POWER AMPLIFIERS IN WIRELESS DIGITAL COMMUNICATION APPLICATIONS - The present invention concerns the field of power amplifiers and in particular the enhancement of the performance of the amplifier by a feedback loop acting on the input signal. We present a method for linearizing a power amplifier circuit having as input signal a digital base-band input signal, (x), a power output signal | 04-28-2011 |
20110102080 | SYSTEMS AND METHODS FOR DISTORTION MEASUREMENT USING DISTORTION-TO-AMPLITUDE TRANSFORMATIONS - The presently invention is directed to ways to measure distortion effects while allowing for the possibility of significant reduction in test cost. An exemplary embodiment of the present invention provides a method for amplifier distortion measurement including comparing a first amplitude response of an output signal from a power amplifier to a second amplitude response of a reference input signal to determine a set of Amplitude-to-Amplitude (“AM-AM”) distortion values. Additionally, the method for amplifier distortion measurement includes equalizing the first amplitude response of the output signal to match the second amplitude response of the reference input signal based on the set of AM-AM distortion values and creating a difference signal based on a comparison of the equalized output signal to the reference input signal. Furthermore, the method for amplifier distortion measurement includes calculating a set of Amplitude-to-Phase (“AM-PM”) distortion values based on a third amplitude response of the difference signal. | 05-05-2011 |
20110109384 | Wireless Signal Corrective Pre-Distortion using Linearly Interpolated Filter Coefficients Derived from an Amplifier Sample Set that is Representative of Amplifier Nonlinearlity - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 05-12-2011 |
20110109385 | Digital Compensation for Parasitic Distortion Resulting from Direct Baseband to RF Modulation - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 05-12-2011 |
20110115559 | SYSTEM FOR REDUCING DISTORTION IN AN ELECTRONIC CIRCUIT USING NONLINEAR FEEDBACK - System and methods for reducing third harmonic distortion produced by nonlinear amplifiers are disclosed. A system may include an amplifier circuit with an amplifier transistor such that the amplifier is capable of exhibiting an amplifier output signal containing third harmonic distortion. Further, a system may include a nonlinear feedback circuit with a first feedback transistor operating in Triode mode that produces a feedback electronic signal containing a feedback third harmonic component. In addition, the nonlinear feedback circuit may be configured to the amplifier circuit in negative feedback such that the feedback third harmonic component of the feedback electronic signal reduces the third harmonic distortion of the amplifier output signal. A system may also provide an output signal that has less third harmonic distortion than the amplifier output signal. | 05-19-2011 |
20110121897 | MEASUREMENT AND CORRECTION OF RESIDUAL NONLINEARITIES IN A DIGITALLY PREDISTORTED POWER AMPLIFIER - A reduced cost method for the measurement and correction of residual nonlinearities in a digitally predistorted transmitter is disclosed. Systems employing predistorters and power amplifiers are calibrated by processing actual input and output signals during the normal operation of the systems. The systems correct memoryless nonlinearities as well as both memoryless and memory based nonlinearities. | 05-26-2011 |
20110140779 | APPARATUS AND METHOD FOR PRE-DISTORTING AND AMPLIFYING A SIGNAL - A method and an apparatus. The apparatus includes: a non-linear amplifier for generating an amplified signal, wherein a non-linearity of the non-linear amplifier, unless compensated by a provision of a pre-distorted signal, broadens a spectrum of the amplified signal from a desired spectrum to a broadened spectrum; a partial signature receiver, for receiving the amplified signal and for generating a sensed partial signature that represents spectral components of the amplified signal that belong only to a sampled spectrum that is narrower than the broadened spectrum; a configuration module, for receiving the sensed partial signature and for selecting, based on the sensed partial signature, a selected set of pre-distortion coefficient values that once applied by a signal processing module provides a best compensation to the non-linearity of the non-linear amplifier out of multiple sets of pre-distortion coefficient values that are available to the configuration module; and a signal processing module, for receiving an input signal and the selected set of pre-distortion coefficient values, and for generating a pre-distorted signal by pre-distorting the input signal by utilizing the selected set of pre-distortion coefficient values and for providing the pre-distorted signal to the non-linear amplifier. | 06-16-2011 |
20110140780 | APARATUS AND A METHOD FOR PROCESSING AND AMPLIFYING A SIGNAL - A method and an apparatus. The apparatus includes at least one sensor for sensing at least one parameter that affects a non-linearity of the non-linear amplifier and for generating at least one parameter indicator; a memory module for storing multiple sets of pre-distortion coefficient values; a retrieval module, coupled to the memory module, for receiving the at least one indicator, for selecting a selected set of pre-distortion coefficient values based on the at least one indicator, and for sending the selected set of pre-distortion coefficient values to a signal processing module; and a signal processing module, configured to receive an input signal, to receive the selected set of pre-distortion coefficient values, and to pre-distort the input signal, using the selected set of pre-distortion coefficient values such as to at least partly compensate for the non-linearity of the non-linear amplifier. | 06-16-2011 |
20110148520 | SYSTEM AND A METHOD FOR SIGNAL PROCESSING - A system for processing an input signal, the system includes: a hardware memory module configured to store a lookup table; and a signal processing module, configured to process the input signal to provide a second signal, and to transmit the second signal to a power amplifier that is characterized by non-linearity and which is adapted to amplify the second signal to provide an amplified signal; wherein the signal processing module is configured to process the input signal in response to at least one filtering parameter to provide the second signal so as to at least partly compensate for the non-linearity of the amplifier; wherein the at least one filtering parameter is retrieved from the lookup table using a first, a second, and a third lookup table indexes, wherein the first index is responsive to a magnitude of the input signal at a first moment, the second index is responsive to a magnitude of the input signal at a second moment, and the third index is responsive to phases of the input signal at the first and the second moments; wherein the system includes a delay circuit for delaying the input signal before the input signal is provided to the signal processing module. | 06-23-2011 |
20110156814 | METHOD AND APPARATUS FOR A POWER SUPPLY MODULATOR LINEARIZER - A method and apparatus for a power amplifier module is described. The module includes a power amplifier and a power supply modulator coupled to the power amplifier. In addition, the module includes an inverter coupled between the power amplifier and the power supply modulator. The inverter provides a predistorted signal to the power amplifier to cancel distortion in the power amplifier provided by the power supply modulator. In addition, the module can include a driver coupled between the power amplifier and the inverter wherein the driver supplies the predistorted signal to the power amplifier. | 06-30-2011 |
20110156815 | MODULATION AGNOSTIC DIGITAL HYBRID MODE POWER AMPLIFIER SYSTEM AND METHOD - A RF-digital hybrid mode power amplifier system for achieving high efficiency and high linearity in wideband communication systems is disclosed. The present invention is based on the method of adaptive digital predistortion to linearize a power amplifier in the RF domain. The present disclosure enables a power amplifier system to be field reconfigurable and support multi-modulation schemes (modulation agnostic), multi-carriers and multi-channels. As a result, the digital hybrid mode power amplifier system is particularly suitable for wireless transmission systems, such as base-stations, repeaters, and indoor signal coverage systems, where baseband I-Q signal information is not readily available. | 06-30-2011 |
20110163805 | Time - Alignment of Two Signals Used for Digital Pre-Distortion - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 07-07-2011 |
20110163806 | DISTORTION COMPENSATION AMPLIFICATION DEVICE - It is intended to increase the efficiency of a distortion compensation amplification device having a pre-distorter | 07-07-2011 |
20110169566 | PREDISTORITION LINEARIZER WITH BRIDGE TOPOLOGY HAVING AN EQUALIZER STAGE FOR EACH BRIDGE ARM - Disclosed is a predistortion linearizer for power amplifiers using a bridge topology, which has the advantages that an equalizer stage is disposed in each of the linear and nonlinear branches. This equalizer stage is used to adjust the frequency response of the complex expansion of the bridge. The equalizers introduce variable transmission functions in the linear and nonlinear bridge branches, so that the linearizer compensates for the individual nonlinear frequency response of a power amplifier, which varies within a manufacturing lot. | 07-14-2011 |
20110175678 | Amplifier Linearizer - The present invention provides an advanced adaptive predistortion linearization technique to dramatically reduce nonlinear distortion in power amplifiers over a very wide instantaneous bandwidth (up to 2 GHz) and over a wide range of amplifier types, input frequencies, signal types, amplitudes, temperature, and other environmental and signal conditions. In an embodiment of the invention, the predistortion linearization circuitry comprises (1) a higher-order polynomial model of an amplifier's gain and phase characteristics—higher than a third-order polynomial model; (2) an adaptive calibration technique; and (3) a heuristic calibration technique. The higher-order polynomial model is generated by introducing, for example, a plurality of multi-tone test signals with varying center frequency and spacing into the power amplifier. From the power amplifier's corresponding output, the nonlinearities are modeled by employing a higher-order curve fit to capture the irregularities in the nonlinear transfer function. Different distortion transfer functions can be implemented for different operating conditions. The adaptive calibration technique is based on a feedback analysis technique, which updates the applicable distortion transfer function by analyzing the error signal between the introduced input signal and the output signal in real-time. The heuristic calibration technique implements different distortion transfer functions based on historical operating conditions and optimal configurations of the power amplifier. | 07-21-2011 |
20110181355 | SIGNAL-COMPENSATION DEVICE AND COMMUNICATION APPARATUS - A signal-compensation device includes a band-limitation unit that performs band limitation on a signal based on a variably adjusted band-set value and externally transmits the signal subjected to the band limitation to an amplifier, a measurement unit that measures a signal level of each of first and second signal components of a feedback signal which is part of an output of the amplifier fed back by a feedback unit to the band-limitation unit, where the each of first and second signal components is based on at least one of a property of variability of the band-set value, a feedback of the feedback signal by the feedback unit, and a nonlinear distortion of the amplifier, and an adjustment unit that adjusts the band-set value based on the signal level of each of the first and second signal components. | 07-28-2011 |
20110187453 | Linearizer incorporating a phase shifter - The present invention pertains to a pre-distorter linearizer that incorporates a balanced-to-unbalanced transmission line transition as a phase shifter to feed the linear and non-linear arms of the linearizer with signals of substantially the same amplitude and with a frequency-independent and substantially 180-degree phase difference. Preferably the balanced-to-unbalanced transmission line transition is a slotline-to-microstrip transition. Several alternatives are shown to enhance the bandwidth performance of the linearizer. Using a slotline-to-microstrip transition as a phase shifter provides for a very physically compact and inexpensive design. Furthermore, the flexibility of the slotline-to-microstrip architecture allows the linearizer to be easily integrated into systems that use both solid-state and vacuum-tube amplifiers. | 08-04-2011 |
20110187454 | DISTORTION COMPENSATING APPARATUS, TRANSMITTING APPARATUS, AND DISTORTION COMPENSATING METHOD - An apparatus includes: a unit that stores the look-up table including distortion compensation coefficients; a unit that selects addresses according to an input signal, acquires coefficients stored at the selected addresses, and performs the predistortion of the input signal by using the acquired coefficients; a unit that calculates an error signal by comparing with the input signal a feedback signal that indicates an output of a power amplifier to which a result of the predistortion is inputted; a unit that calculates coefficients from the error signal and the acquired coefficients by using the adaptive algorithm; a unit that, for each of the selected addresses, selects coefficients as adequate coefficients from among the calculated coefficients according to the error signal; and a unit that, for each of the selected addresses, calculates an average value of the adequate coefficients and replaces a stored coefficient in the look-up table with the average value. | 08-04-2011 |
20110187455 | Adaptive Digital Predistortion Device and Method - The present invention relates to an adaptive digital predistortion device and method. The adaptive digital predistortion device comprising: a predistortion unit for predistorting an input signal according to a predistortion parameter stored in a look-up table; a cost function generation unit for generating a cost function; a fixed segment point determination unit for determining a fixed segment point; and an update unit for updating parameters (u | 08-04-2011 |
20110204975 | CALCULATING APPARATUS, DISTORTION CORRECTING APPARATUS, AMPLIFYING APPARATUS, AND CALCULATING METHOD - A calculating apparatus includes a first state variable calculating unit that calculates first state variables respectively having a memory effect and being of an amplifier that causes signal distortion; an amplifier model unit that based on the calculated first state variables, calculates the signal distortion caused by the amplifier, as a distortion characteristic; and an output unit that outputs the calculated distortion characteristic. | 08-25-2011 |
20110210788 | SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE AND TRANSMISSION AND RECEPTION SYSTEM - A semiconductor integrated circuit device comprising a linearizer that has a plurality of switchable first gain characteristics, the linearizer switching to the first gain characteristic to generate an intermediate signal from an input signal by using the switched first gain characteristic, and outputting the intermediate signal to a circuit having a second gain characteristic, wherein the linearizer includes: a linearization unit that has at least one of first rectifier, and linearizes the input signal; and a linearization reducing unit that has a plurality of second rectifiers having polarity opposite to polarity of the first rectifier and a first switching unit selecting at least one of the second rectifiers based on a control signal, the linearization reducing unit being connected in parallel to the linearization unit and reducing linearization of the input signal by the linearization unit. | 09-01-2011 |
20110210789 | POWER SERIES DIGITAL PREDISTORTER AND DISTORTION COMPENSATION CONTROL METHOD THEREOF - Coefficients W | 09-01-2011 |
20110221524 | RADIO APPARATUS, DISTORTION CORRECTION DEVICE, AND DISTORTION CORRECTION METHOD - When a distortion correction coefficient, which is calculated according to a signal input to a power amplifier and a signal output from the power amplifier, is larger than a first threshold, a distortion correction coefficient corresponding to the input signal is updated to the first threshold. When the calculated distortion correction coefficient is equal to or smaller than the first threshold, the distortion correction coefficient corresponding to the input signal is updated to the calculated distortion correction coefficient. | 09-15-2011 |
20110221525 | RADIO APPARATUS, DISTORTION CORRECTION DEVICE, AND DISTORTION CORRECTION METHOD - An error between the power of an input signal, which is input to a power amplifier, and the power of an output signal, which is output from the power amplifier, is calculated. The calculated error is normalized according to the power of the input signal or the power of the output signal. A distortion correction coefficient, which is stored in a predetermined storage unit in association with the power of the input signal, is updated using the normalized error. | 09-15-2011 |
20110221526 | METHOD AND APPARATUS FOR A GAIN CONTROL CIRCUIT VIA A HIGH FREQUENCY SIGNAL - A gain control amplifier provides amplitude variation of an input signal that is coupled to the amplifier, by adding or combining a higher frequency signal that overdrives or distorts the amplifier to one or more degree(s), to provide the gain variation of the input signal. A predistortion circuit may be included to further reduce distortion of the input signal at the output of the amplifier. | 09-15-2011 |
20110221527 | DIGITAL PREDISTORTION APPARATUS AND METHOD FOR IMPROVING PERFORMANCE USING PEAK LEVEL EXPANSION - A method an apparatus improve linearization performance and reduce a convergence time of a Digital Pre-Distorter of a power amplifier. An input signal is received. A peak level of the input signal is expanded based on an expansion threshold. And the expanded peak level of the input signal is linearized through Digital Pre-Distorter (DPD) training on the expanded input signal. | 09-15-2011 |
20110227643 | DISTORTION COMPENSATING APPARATUS, AMPLIFYING APPARATUS, TRANSMITTING APPARATUS, AND DISTORTION COMPENSATING METHOD - A distortion compensating apparatus that compensates signal distortion caused by an amplifier includes a distortion compensating process unit that using a distortion compensation coefficient, compensates distortion of an input signal; a memory unit storing therein the distortion compensation coefficient; and an address generating unit that generates a first address that is based on electrical power of the input signal and is for acquiring the distortion compensation coefficient from the memory unit, and a second address that is based on any one among the electrical power, phase of the input signal and amplitude of the input signal, is for acquiring the distortion compensation coefficient from the memory unit, and is normalized in a normalizing range determined according to the electrical power of the input signal. The distortion compensating process unit acquires the distortion compensation coefficient from the memory unit, based on the first and the second addresses to compensate the distortion. | 09-22-2011 |
20110227644 | DISTORTION COMPENSATING APPARATUS, AMPLIFYING APPARATUS, TRANSMITTING APPARATUS, AND DISTORTION COMPENSATING METHOD - A distortion compensating apparatus that compensates signal distortion caused by an amplifier includes a distortion compensating process unit that using a distortion compensation coefficient, compensates distortion of an input signal; a memory unit that stores the distortion compensation coefficient; and an address generating unit that generates a first address that is based on electrical power of the input signal and for acquiring the distortion compensation coefficient from the memory unit and that generates a second address that is based on a phase of the input signal and for acquiring the distortion compensation coefficient from the memory unit. The distortion compensating process unit acquires the distortion compensation coefficient from the memory unit based on the first and the second addresses to compensate the distortion. | 09-22-2011 |
20110234314 | Adaptive compensation systems for mitigating distortion due to nonlinear power amplifiers - A method for pre-processing a signal prior to receipt of the signal by a non-linear device (NLD) to compensate for AM-AM distortion and AM-PM distortion of the signal by the NLD. The method includes generating a modified amplitude r | 09-29-2011 |
20110234315 | Power Amplifier Linearization Using Cancellation-Based Feed Forward Methods and Systems - Linearizers can improve the linearity of power amplifiers by canceling or reducing amplitude of non-linearity components, (e.g., IM | 09-29-2011 |
20110254623 | DISTORTION COMPENSATION CIRCUIT - Disclosed is a distortion compensation circuit that efficiently compensates for distortion. A distortion compensation circuit ( | 10-20-2011 |
20110254624 | DISTORTION COMPENSATING CIRCUIT AND RADIO BASE STATION - A distortion compensation circuit capable of realizing highly accurate distortion compensation by updating a model even under a situation in which the appearance frequency of an input signal having a maximum value is low. A DPD processor | 10-20-2011 |
20110260792 | DISTORTION COMPENSATION DEVICE, RADIO COMMUNICATION DEVICE, AND DISTORTION COMPENSATION METHOD - A distortion compensation device includes a distortion compensation unit which compensates for a distortion generated in a power amplifier by using a polynomial in which a signal to be input into a power amplifier is raised to a power of a degree N (N is an integer larger than 0) and the raised signal is delayed by a delay number K (K is an integer larger than 0), and a polynomial adjusting unit which adjusts the degree N or the delay number K of the polynomial based on a comparison between a prescribed value, which indicates a degree of variation of the distortion generated in the power amplifier and a threshold value. | 10-27-2011 |
20110267143 | SYSTEM FOR REDUCING NOISE IN A CATV HOME AMPLIFIER UPSTREAM PATH AND A METHOD THEREOF - A system for control of noise in a cable TV upstream path of a bi-directional cable TV home amplifier system that is positioned in the premises of the end user includes a noise control circuit and a coupler element that couples between the noise control circuit and the cable TV upstream path. The system further includes an amplifier part that is disposed on the upstream path. The noise control circuit connects or disconnects the cable TV upstream path depending on the level of signal passing through the cable TV upstream path. Namely, when the level of a signal that passes through the upstream path is lower than a predefined signal threshold, the noise control circuit disconnects the upstream path, and when the level of the signal is greater than a predefined signal threshold, the noise control circuit connects the upstream path. | 11-03-2011 |
20120007672 | Linearization Device for a Power Amplifier - A linearization device for a power amplifier using adaptive digital baseband predistortion includes a pre-inverse block receiving a complex discretized input signal {tilde over (x)} | 01-12-2012 |
20120019320 | Signal alignment for envelope tracking system - There is disclosed a method for determining the timing misalignment between a power supply and an output in an envelope tracking amplification stage, the method including the steps of: estimating a distortion parameter in the amplification stage; and determining a timing error in dependence on the estimated distortion parameter. | 01-26-2012 |
20120025909 | DISTORTION COMPENSATION APPARATUS AND APPARATUS AND METHOD FOR TRANSMITTING SIGNAL - A distortion compensation apparatus and an apparatus and method for transmitting a signal are provided. The distortion compensation apparatus can extract precise distortion information by adding an additional signal to an input signal during the compensation of distortion in a nonlinear apparatus, and can linearize the nonlinear properties of the nonlinear apparatus using the distortion information. The apparatus for transmitting a signal can output a signal linearized by the same method as that used by the distortion compensation apparatus. | 02-02-2012 |
20120032739 | DIGITAL PREDISTORTION CIRCUIT WITH EXTENDED OPERATING RANGE AND A METHOD THEREOF - A digital predistortion circuit and method with extended operating range includes a predistortion function, a D/A converter, a multiplier for performing frequency translation and a power amplifier. The digital predistortion circuit includes a multiplier for receiving a signal to be transmitted and a gain correction factor, multiplying the gain correction factor with the signal to be transmitted, and outputting a result of the multiplication to the predistortion function, as well as a device for calculating the gain correction factor by using a predetermined reference gain and an estimated gain of the power amplifier, and outputting the calculated gain correction factor to the multiplier, whereby a gain of the power amplifier is quickly corrected. The digital predistortion circuit and the method thereof produce acceptable results for a more expanded range of TX power levels. | 02-09-2012 |
20120068768 | TRANSMISSION APPARATUS AND DISTORTION COMPENSATION METHOD - A transmission apparatus includes an analog digital converter that performs sampling on a demodulated signal obtained by demodulating a part of an output signal, which is produced by amplifying a modulated signal of a baseband signal including a plurality of signals having frequencies separated from each other, at a sampling frequency lower than a frequency of a given intermodulation distortion component and converting the demodulated signal into a digital signal, a detection section that detects an aliasing component of the given intermodulation distortion component produced by the conversion of the analog digital converter, and a distortion compensation section that compensates an input signal to be modulated for the given intermodulation distortion component in accordance with the detected aliasing component. | 03-22-2012 |
20120081178 | POWER AMPLIFICATION DEVICE AND METHOD FOR ACQUIRING POWER ADJUSTING COEFFICIENT - An embodiment of the invention discloses a power amplification device and method and a method for acquiring a power adjusting coefficient. The power amplification device according to one embodiment of the invention includes: a power control module configured to perform power adjusting on an input signal; a power amplification module configured to perform power amplification on the signal subjected to the power adjusting by the power control module; and a pre-distortion module configured to compensate for nonlinear characteristic of the power amplification module; wherein, said power control module is coupled between said pre-distortion module and said power amplification module in series; alternatively, said pre-distortion module is coupled between said power control module and said power amplification module in series. With the embodiment of the invention, a transmitter can be provided with a spectrum including a low side lobe even upon startup. | 04-05-2012 |
20120086507 | POWER AMPLIFIER LINEARIZATION METHOD AND APPARATUS - Disclosed is a method and apparatus for linearizing a power amplifier using a digital signal process (DSP), and particularly, is a method and apparatus for effectively linearizing an amplifier which has a plurality of distortion generating sources. To this end, there is a plurality of compensation methods and compensation units which can generate inverse distortion signals corresponding to the distortion components outputted by the plurality of distortion generating sources, thereby making it possible to provide superior linearity. | 04-12-2012 |
20120092067 | METHOD AND APPARATUS FOR LINEARIZING A NON-LINEAR POWER AMPLIFIER - An apparatus and method for linearizing a non-linear power amplifier. The method comprises: performing an iteration algorithm by using a desired output signal of the non-linear power amplifier, to calculate an input signal of the non-linear power amplifier, whereby with the calculated input signal of the non-linear power amplifier, the non-linear power amplifier is linearized. The apparatus and method can produce a signal on the output of the non-linear power amplifier with an arbitrarily high quality of performance. | 04-19-2012 |
20120098596 | POWER AMPLIFIER APPARATUS, DISTORTION COMPENSATION COEFFICIENT UPDATING METHOD, AND TRANSMISSION APPARATUS - A power amplifier apparatus that includes a processor that performs a first distortion compensation processing on an input signal using a distortion compensation coefficient to obtain a first signal and an amplifier that amplifies the first signal. The processor performs a second distortion compensation processing the amplified signal using the distortion compensation coefficient to obtain a second signal and updates the distortion compensation coefficient to enable convergence between the first signal and the second signal. | 04-26-2012 |
20120105153 | POP SOUND REDUCTION CIRCUIT AND AUDIO CIRCUIT HAVING SUCH POP SOUND REDUCTION CIRCUIT FOR USE IN AUDIO AMPLIFIER - A disclosed pop sound reduction circuit reducing generation of pop sound at activation or deactivation of an audio amplifier includes a reference voltage circuit generating a reference voltage, a differential amplifier circuit having first and second inputs to amplify the audio signal based on a comparison between the first and second inputs, a triangular voltage generator circuit generating a triangular voltage, a voltage current convertor circuit generating a current proportional to the triangular voltage, a capacitor charged with the generated current to generate a voltage corresponding to the generated current, a constant voltage circuit generating a constant voltage, and a control circuit switching the triangular voltage into the constant voltage to be applied to the voltage current convertor circuit so as to increase the generated voltage if the voltage generated by the capacitor is below the reference voltage when the triangular voltage is equal to or below a predetermined voltage. | 05-03-2012 |
20120119831 | Orthogonal Basis Function Set for Digital Predistorter - A predistorter applies a distortion function to an input signal to predistort the input signal. The output of the distortion function is modeled as the sum of the output signals from the orthogonal basis functions weighted by corresponding weighting coefficients. Techniques are described for orthogonalizing the basis function output signals depending on the distribution of the input signal. | 05-17-2012 |
20120119832 | Joint Process Estimator with Variable Tap Delay Line for use in Power Amplifier Digital Predistortion - Methods and circuits for pre-distorting a signal to compensate for distortion introduced by an electronic device operating on the signal. In an example method, first and second signal samples representing the input and output of the electronic device are generated. The first and second signal samples are spaced at unit-delay intervals, and each of the second signal samples corresponds in time to one of the first signal samples. Pre-distortion weights are then calculated from the first and second signal samples, the pre-distortion weights corresponding to a pre-distortion model comprising a lattice-predictor memory model structure having multiple delays and having at least one multi-unit delay interval between adjacent delays. The calculated pre-distortion weights are then applied to the input signal, using a predistorter with a structure corresponding to the lattice-predictor memory model, to produce a pre-distorted input signal for input to the electronic device. | 05-17-2012 |
20120133433 | APPARATUS FOR AND METHOD OF CONTROLLING A PREDISTORTER, AND METHOD OF DETECTING POWER CONTROL STATE - This invention relates to an apparatus for and a method of controlling a predistorter, and a method of detecting power control state. The method of controlling a predistorter, which is for predistorting a signal input into a power amplifier, comprises storing predistortion coefficients used by the predistorter; acquiring indices each indicative of an output power of the power amplifier; detecting, based on the indices acquired in the acquiring, whether the power amplifier is in a state of undergoing power control; and supplying the stored predistortion coefficients to the predistorter when it is detected that the power amplifier is in the state of undergoing power control, or supplying, when it is detected that the power amplifier is not in the state of undergoing power control, to the predistorter predistortion coefficients calculated by a unit that performs predistortion coefficient adaptive updating operation. | 05-31-2012 |
20120133434 | METHOD AND APPARATUS FOR IMPROVING DIGITAL PRE-DISTORTION PERFORMANCE - A digital pre-distortion system and method are provided. The method includes performing a digital pre-distortion operation; and limiting an input of the power amplifier to be no greater than a limit threshold. | 05-31-2012 |
20120139629 | Third Order Intermodulation Cancellation by In-Line Generated Signal - An actual linear amplifier distorts an input signal, such as an RF signal, and generates third order intermodulation (IM3) products. A single-port predistortion circuit is connected at a single node of an input line to the amplifier via an AC coupling capacitor. The fundamental frequency of the input signal is applied to a forward biased diode junction. The current through the diode is applied to a second capacitor. The appropriate setting of a tuning device, such as a tunable resistor or a tunable capacitor, causes the predistortion circuit to invert the second harmonic generated by the diode. The inverted second harmonic signal is applied to the single node of the input line to add predistortion to the signal applied to the amplifier. The predistortion cancels or substantially reduces the IM3 products at the output of the amplifier. | 06-07-2012 |
20120154038 | Multi-band wideband power amplifier digital predistorition system and method - A high performance and cost effective method of RF-digital hybrid mode power amplifier systems with high linearity and high efficiency for multi-frequency band wideband communication system applications is disclosed. The present disclosure enables a power amplifier system to be field reconfigurable and support multiple operating frequency bands on the same PA system over a very wide bandwidth. In addition, the present invention supports multi-modulation schemes (modulation agnostic), multi-carriers and multi-channels. | 06-21-2012 |
20120154039 | Generation of pre-distortion coefficients - There is disclosed a method for generating pre-emphasis coefficients for a pre-emphasis stage of a non-linear distorting device, the method comprising the steps of: capturing, for a given time period, samples of an input signal and samples of an output signal; determining the direction of an error between the captured samples; adjusting the input signal in a direction to reduce the error to generate an estimate of the pre-distorted input signal; generating updated pre-distortion coefficients in dependence on the estimate of the pre-distorted input signal and generated pre-distortion coefficients for one or more previous time periods. | 06-21-2012 |
20120154040 | PREDISTORTER FOR COMPENSATING FOR NONLINEAR DISTORTION AND METHOD THEREOF - The predistorter may include: a predistortion filter predistorting an input signal to provide an output signal; a predistortion output estimation unit estimating the characteristics of a nonlinear device based on a signal processed by the nonlinear device and the output signal, and calculating a desired output signal of the predistortion filter by using the estimated characteristics of the nonlinear device; and an adaptive algorithm driving unit comparing the output signal with the desired output signal to output an error as a comparison result, calculating a filter coefficient according to which the calculated error is minimized, and providing the calculated filter coefficient to the predistortion filter in order to update a filter coefficient of the predistortion filter. | 06-21-2012 |
20120154041 | PREDISTORTION APPARATUSES AND METHODS - Provided is a predistortion apparatus which performs predistortion by reflecting a memory effect when linearizing an output of a nonlinear device using a wideband signal. The predistortion apparatus includes a predistortion unit and a coefficient extraction unit. The predistortion unit selects and outputs one of outputs of the sub-predistorters as an output signal according to intensity of an input signal. The coefficient extraction unit selects one of a plurality of coefficient extractors according to intensity of a nonlinear signal which is generated in response to the output signal, extracts a plurality of predistortion coefficients with the nonlinear signal and the output signal, and delivers the extracted predistortion coefficients to the predistortion unit. Accordingly, the memory effect is reflected even when the input signal is a wideband signal. | 06-21-2012 |
20120194270 | Broadband Linearization Module And Method - A system including a power amplifier and a pre-distortion module coupled to the power amplifier. The pre-distortion module includes one or more smaller versions of the power amplifier to generate a pre-distortion signal that compensates for any memory-effect or inertia present in the power amplifier with application on frequency hopping and larger (up to 1 octave) instantaneous bandwidth communication systems. | 08-02-2012 |
20120194271 | AMPLIFYING DEVICE AND WIRELESS TRANSMISSION DEVICE USING THE SAME - An amplifying device | 08-02-2012 |
20120206199 | Method and apparatus to linearize transconductors by predistortion - A transconductor for providing an output current that is linear in the input voltage (Vin) comprises a main output transconductor (Ms, Mc) and a model transconductor (Msr | 08-16-2012 |
20120229209 | POWER AMPLIFICATION DEVICE, TRANSMITTER, AND POWER AMPLIFICATION CONTROL METHOD - A power amplifier amplifies a signal. An error signal calculating unit calculates an error signal in accordance with an input signal and an output from the power amplifier. A distortion compensation unit performs predistortion on the input signal by using distortion compensation coefficients that are generated in accordance with a plurality of delay signals obtained by giving different amounts of delay to the input signal and by using an error signal and outputs the input signal subjected to the predistortion to the signal amplifying unit. A tap interval control unit controls the delay intervals of the delay signals that are used for the predistortion performed by the distortion compensation unit in accordance with signal correlation information calculated from the input signal. | 09-13-2012 |
20120235741 | TIMING ALIGNMENT FOR POWER AMPLIFIER - There is described a method of controlling signal alignment in a power amplifier, comprising: receiving an input signal to be amplified; receiving a supply voltage for the power amplifier, the supply voltage being derived in dependence on the signal to be amplified; amplifying the input signal to produce an output signal; comparing the output signal with a plurality of distorted versions of the input signal, each distorted version of the input signal being associated with a different time delay value; and adjusting the timing of either the input signal or the supply voltage by an amount in dependence on a time delay value determined to be associated with a distorted version of the input signal which most closely matches the output signal. | 09-20-2012 |
20120242405 | Frequency-Desensitizer for Broadband Predistortion Linearizers - Systems, apparatus and methods that provide broadband predistortion linearizers including simple frequency desensitizers to maintain substantially the same predistortion in a relatively broad frequency band. For example, a broadband predistorter can include a nonlinear component to predistort the drive signal, and a simple frequency desensitizer to compensate the frequency dependence of the nonlinear component. In particular implementations, the nonlinear component can have a frequency dependent impedance that substantially changes across the broad operating bandwidth and the frequency desensitizer can include resistive and reactive elements, such as a resistor (R), an inductor (L), and a capacitor (C) in a resonator configuration, to compensate for the frequency-dependence of the nonlinear component in the broad operating bandwidth. | 09-27-2012 |
20120256686 | RADIO FREQUENCY (RF) AMPLIFIER UTILIZING A PREDISTORTION CIRCUIT AND RELATED TECHNIQUES - An apparatus and technique for operating an RF amplifier having a pre-distortion processor and a drain modulation circuit includes generating a compensating drain bias signal having a value which is a function of an RF input signal, a sampled RF output signal and a sampled drain bias signal. The compensating drain bias signal is applied to the RF amplifier. By sampling both the drain bias signal and the RF output signal and providing drain feedback and RF output feedback signals to a pre-distortion processor, RF amplifier distortions can be linearized enabling the RF amplifier to operate over a bandwidth which exceeds the bandwidth of the drain modulation circuit (i.e., the RF bandwidth can exceed the bandwidth of the drain modulator). | 10-11-2012 |
20120256687 | Pre-distortion for a Radio Frequency Power Amplifier - Coefficients of a pre-distorter are determined for correction of distortion of a signal amplified by a radio frequency amplifier by sampling the signal at the pre-distorter input to generate a plurality of input samples and sampling the signal at the amplifier output to generate a plurality of output samples, each of the output samples corresponding to one of the input samples, calculating a figure of merit for one or more of the input samples on the basis of the one or more of the input samples, selectively updating a previously selected set of input samples with said one or more input samples on the basis of the calculated figure of merit, whereby to generate an updated selected set and determining the coefficients of the pre-distorter on the basis of the input samples in the updated selected set and the corresponding output samples. | 10-11-2012 |
20120256688 | AMPLIFYING DEVICE AND SIGNAL PROCESSING DEVICE - Signal timing adjustment in an amplifying device is appropriately performed by phase adjustment by a digital filter. The amplifying device includes an amplifier; an amplitude-voltage converting unit 12 that performs a desired process on a signal relating to operation of the amplifier, whereby the signal is band-broadened; and a timing adjusting unit 15 | 10-11-2012 |
20120262234 | POWER AMPLIFIER WITH ADVANCED LINEARITY - An amplifier is provided. The amplifier includes an input matching unit suppressing harmonic components of an input signal; a high power amplification unit amplifying a signal suppressed by the input matching unit; and an output matching unit suppressing harmonic components of an output signal amplified by the high power amplification unit. | 10-18-2012 |
20120280749 | SYSTEMS AND METHODS FOR MITIGATING SPECTRAL REGROWTH FROM NON-LINEAR SYSTEMS - Various embodiments are directed to a non-linear amplifier system comprising a reference output generator, an adaptive filter, a amplitude distortion (AM-AM) compensator, a phase distortion (AM-PM) compensator, an adaptive spectrum controller and a non-linear system. The reference output generator may receive an input signal and generating a reference output. The adaptive filter may generate a modified input signal based on the input signal and the reference output. The AM-AM compensator may act on the modified input signal to compensate for AM-AM distortion. The phase distortion (AM-PM) compensator may act on the modified input signal to compensate for AM-PM distortion. The adaptive spectrum controller may provide parameters to the adaptive filter to minimize the power spectral density (PSD) of an output of the non-linear amplifier system in a stop-band and maximize the PSD of the output of the non-linear amplifier system in a pass-band. | 11-08-2012 |
20120286863 | APPARATUS AND METHOD OF DIGITAL PREDISTORTION FOR POWER AMPLIFIERS WITH DYNAMIC NONLINEARITIES - Power amplifiers (PAs) using a Doherty or other power output level sensitive configuration have been employed for several years in telecommunications (as well as other applications) to take advantage of efficiency gains. For many of these applications, baseband signals are predistorted to compensate for nonlinearities in the PAs, but because there is a “switching event” in a Doherty-type amplifier (for example), the nonlinearities become dynamically varying. As a result, digital predistortion (DPD) becomes increasingly difficult to perform. Here, DPD modules are provided that adapt to changes in dynamically varying PAs based on a determination of the average power or other relevant metric prior to transmission. | 11-15-2012 |
20120286864 | Linearization in the Presence of Phase Variations - In one embodiment, a non-linear power amplifier generates an amplified output signal based on a pre-distorted signal generated by a digital pre-distorter based on an input signal. A feedback path generates a feedback waveform based on the amplified output signal. The feedback waveform is aligned in time with the input signal at the waveform level to identify a corresponding reference waveform. The feedback waveform and the corresponding reference waveform are both divided into a plurality of sub-waveforms. Each feedback sub-waveform is independently aligned in phase with its corresponding reference sub-waveform. The resulting plurality of phase-aligned feedback sub-waveforms are then combined to form a hybrid-aligned waveform that is compared to the reference waveform to adaptively update the digital pre-distorter. | 11-15-2012 |
20120286865 | Pre-Distortion Architecture for Compensating Non-Linear Effects - An input signal is pre-distorted to reduce distortion resulting from subsequent signal amplification. Frequency-dependent pre-distortion is preferably implemented in combination with frequency-independent pre-distortion, where the frequency-dependent pre-distortion is generated by expanding the derivative of a product of a pre-distortion function and the input signal and then relaxing constraints on the pre-distortion function and/or on frequency-dependent filtering associated with the frequency-dependent pre-distortion. In one implementation, four different frequency-dependent pre-distortion signals are generated for the expansion using up to four different pre-distortion functions and up to four different frequency-dependent filters. | 11-15-2012 |
20120286866 | AMPLIFIER PERFORMANCE STABILIZATION THROUGH PREPARATORY PHASE - A method and related systems for amplifier performance stabilization of a digitally predistorted RF power amplifier are disclosed. The characteristics of power amplifiers change as a function of temperature making adaptive digital predistortion highly problematic during initial application of an RF signal to a power amplifier. Embodiments disclose a method and systems in which the power amplifier is taken through a preparatory phase before the RF signal is applied to the power amplifier and the digital predistortion calculation starts. This is achieved by increasing the quiescent current of the power stages beyond nominal values for a rapid warm up and readjusting to its normal bias point when the radio frequency signal is applied and the digital predistortion is turned on. | 11-15-2012 |
20120286867 | AMPLIFIER APPARATUS, RADIO TRANSMITTING APPARATUS INCLUDING SAME, AND METHOD OF ADJUSTING GAIN OF AMPLIFIER APPARATUS - An object of the present invention is to provide an amplifier apparatus | 11-15-2012 |
20120306573 | SIGNAL PROCESSING ARRANGEMENT AND SIGNAL PROCESSING METHOD - A signal processing apparatus for processing an input signal (x) has an adaptive predistorter, an amplifier and a down-converter. The amplifier is configured to amplify a processed signal (y′) to obtain an amplified signal (y″). The down-converter is configured to multiply a version of the processed signal (y′) with a version of the amplified signal (y″), one of the signal versions being phase shifted, to obtain a first down-converted signal (z | 12-06-2012 |
20130002348 | AMPLIFIER WITH IMPROVED NOISE REDUCTION - An amplifier with improved noise reduction is disclosed. In one implementation, an amplifier is provided that includes a main output stage configured to output an amplified signal at a main output terminal, a secondary output stage configured to output a copy of the amplified signal at a secondary output terminal, and a signal coupler configured to provide a variable resistance coupling between the secondary output terminal and the main output terminal to reduce noise at the main output terminal. | 01-03-2013 |
20130009701 | Power Amplifier Pre-Distortion - The present invention is directed to systems and methods for reducing the distortion of power amplifiers. In particular, methods and systems are described that enable a determination of a pre-distortion correction signal to be determined, which when added to the nominal signal, a reduction in the distortion of the power amplifier results. In addition, methods and systems are described that enable calibration of individual power amplifiers to be accomplished for use with the above described approach. More specifically, the methods and systems are described for use in a MIMO application. These approaches may be applied to on-chip power amplifiers, off-chip power amplifiers, or any combination thereof. | 01-10-2013 |
20130009702 | Pre-Distortion for a Radio Frequency Power Amplifier - Coefficients of a pre-distorter are determined for distortion correction of a signal amplified by a radio frequency amplifier by sampling the signal at the pre-distorter input to generate a plurality of input samples and sampling the signal at the amplifier output to generate a plurality of output samples, each of the output samples corresponding to one of the input samples, calculating a figure of merit for one or more of the input samples on the basis of the one or more input samples, selectively updating a previously selected set of input samples with the one or more input samples on the basis of the calculated figure of merit, whereby to generate an updated selected set and determining the coefficients of the pre-distorter on the basis of the input samples in the updated selected set and the corresponding output samples. | 01-10-2013 |
20130015917 | DISTORTION COMPENSATION APPARATUS, TRANSMITTER, AND DISTORTION COMPENSATION METHODAANM ISHIKAWA; HiroyoshiAACI YokohamaAACO JPAAGP ISHIKAWA; Hiroyoshi Yokohama JPAANM Nagatani; KazuoAACI YokohamaAACO JPAAGP Nagatani; Kazuo Yokohama JPAANM Fudaba; NobukazuAACI YokohamaAACO JPAAGP Fudaba; Nobukazu Yokohama JP - A distortion compensation apparatus includes an amplifying unit, a plurality of distortion compensation coefficient storage units, a first address generating unit, a second address generating unit, and a distortion compensating unit. The amplifying unit amplifies an input signal. A plurality of distortion compensation coefficient storage units store the distortion compensation coefficients for compensating for the distortion of the amplifying unit by being associated with two different addresses. The first address generating unit generates a first address based on the current input signal. The second address generating unit generates a second address different from the first address based on the previous input signal. The distortion compensating unit obtains the distortion compensation coefficient corresponding to a combination of the first and second addresses from each of the distortion compensation coefficient storage units and performs a pre-distortion processing for the current input signal to the amplifying unit using the obtained distortion compensation coefficient. | 01-17-2013 |
20130033317 | PRE-DISTORTION FOR FAST POWER TRANSIENT WAVEFORMS - An apparatus and a method select and use parameter values for an RF power amplifier linearizer to pre-distort the input signals of a power amplifier, so as to achieve a linear output response in the power amplifier. The apparatus and the method select from a number sets of parameter values, each set of parameter values corresponding to a different output power range of the power amplifier. The set of parameters include a coefficient vector tailored for the particular output power range for that set. The power amplifier input power is repeatedly measured and filtered at various time intervals. The input power measurements may be filtered by a fast attack/slow decay filter, which follows the peaks of the measurements under operation of the fast attack portion of the filter and provides a low variance during operation of the slow decay portion of the filter. The coefficient values for the predistortion linearization of the power amplifier is adapted dynamically, in response to changes in the input power level of the power amplifier. In one embodiment, hysteresis is used to reduce the rate at which the predistortion linearizer hops between two sets of the parameter values. Using the apparatus and the method, good ACLR across a wide range of power amplifier output power is achieved. Such characteristics are particularly advantageous in a system in which waveforms having fast power transients are present. | 02-07-2013 |
20130076437 | COMBINED PREDISTORTER AND FEEDFORWARD CORRECTOR APPARATUS SUITABLE FOR USE IN A TRANSMITTER - In accordance with the present disclosure, there is provided a predistorter combined with a feedforward corrector that addresses power dissipation of the feedforward error path while maintaining a sufficiently simple digital predistortion model so as to further minimize power dissipation without sacrificing linearity. | 03-28-2013 |
20130082773 | LINEARIZATION OF POWER AMPLIFIERS THROUGH DIGITAL IN-BAND PREDISTORTION FOLLOWED BY ANALOG PREDISTORTION - A system for implementing linearization of a radio frequency (RF) power amplifier (PA) in a base station, as well as various component circuitry for implementing said system. By means of a smart partitioning of the signal processing for predistortion between the analog domain and the digital domain, a more linear relationship between the digital input data and the output RF signal is achieved. Linearization of the PA's output signal is obtained using a mixed-signal apparatus. The digital baseband signal enters the RF signal source. The RF signal source comprises an in-band predistortion circuit, a micro-controller and digital modulator. The output of the digital modulator is an RF signal that enters the PA module. The PA module is composed of the PA and the RF power amplifier linearizer (RFPAL). The RFPAL comprises an RF predistortion circuit, and RF signal analyzer and a microcontroller. | 04-04-2013 |
20130082774 | LINEARITY POWER AMPLIFICATION DEVICE - A linearity power amplification device is provided. The device comprises a divider, a combiner, n−1 first signal paths, and a second signal path coupled between the divider and the combiner. The first signal path comprises a main invariable attenuator connected to the divider, a first power amplifier connected to the combiner, and a first attenuator and a first shifter coupled between the first power amplifier and the main invariable attenuator. The second signal path comprises a main amplification circuit, and an error calibration circuit. | 04-04-2013 |
20130082775 | Systems and Methods for Adaptive Power Amplifier Linearization - An exemplary system comprises a linearizer, a power amplifier, and a feedback block. The linearizer may be configured to use a predistortion control signal to add predistortion to a receive signal to generate a predistorted signal. The power amplifier may be configured to amplify power of the predistorted signal to generate a first amplified signal. The power amplifier may also add high side and low side amplifier distortion to the predistorted signal. The high side and low side amplifier distortion may cancel at least a portion of the predistortion. The feedback block may be configured to capture a feedback signal based on a previous amplified signal from the power amplifier, to determine high side and low side distortion of the captured feedback signal, and to generate the predistortion control signal based on the determined high side and low side distortion. | 04-04-2013 |
20130099862 | LINEARIZATION OF BROADBAND POWER AMPLIFIERS - An RF linearizer and an associated method are provided for linearizing a power amplifier. The RF linearizer may include: (a) a quadrature up-converter for up-converting a baseband input signal that is to be transmitted by the power amplifier; (b) an RF analog predistorter controlled by a set of coefficients for predistorting the up-converted input signal; (c) a down-converter for down-converting an output signal of the power amplifier; (d) an error monitor receiving the down-converted output signal and the input signal for providing an error signal; and (e) a signal analyzer receiving the error signal, the signal analyzer using an out-of-band power spectrum of the error signal to optimize the set of coefficients. The input signal may have an in-phase component and a quadrature component. | 04-25-2013 |
20130113559 | DEVICE AND METHOD FOR PRE-DISTORTING AND AMPLIFYING A SIGNAL BASED ON AN ERROR ATTRIBUTE - A method and a device may be provided. The device may include a non-linear amplifying circuit arranged to apply a non-linear gain function on an analog signal to provide an amplified signal; an input circuit, arranged to clip I channel and Q channel digital input signals supplied from a digital transmitter, to provide clipped I-channel and Q-channel digital signals; a pre-distortion circuit, arranged to pre distort the clipped I channel and Q channel digital signals such as to at least partially compensate for a non linearity of the non linear gain function, to provide pre-distorted I-channel and Q-channel digital signals; a mixed signal circuit for converting the pre-distorted I-channel and Q-channel digital signals to the analog signal; a reconstruction circuit, arranged to receive at least a portion of the amplified signal and to generate reconstructed I-channel and Q-channel signals; and a control circuit, arranged to: calculate an error attribute based on (a) the clipped I-channel and Q-channel digital signals, and (b) the reconstructed digital I-channel and Q-channel signals; and to affect at least one operational parameter of the non-linear amplifying circuit in response to the error attribute. | 05-09-2013 |
20130120062 | ADAPTIVE LINEARIZER WITH NARROWBAND FEEDBACK PATH - An ISI Replica unit is provided, which produces interference components similar to one due to LPF into the output of HPA MODEL unit. An HPA MODEL unit models the characteristic of HPA using the output signal of the predistorter and an error signal obtained by subtracting a feedback signal from the output of the ISI Replica so that the error signal approaches zero. The feedback signal is used after filtration by LPF, thereby including interference components. The error signal obtained by the feedback signal after LPF and the output signal of ISI Replica unit includes few interference components, thereby modeling by the HPA MODEL unit becomes accurate and the linearization performances become better. | 05-16-2013 |
20130141160 | POWER SERIES DIGITAL PREDISTORTER AND CONTROL METHOD THEREOF - A PAPR observation unit that measures PAPR in a distributed output of an input signal and PAPR in a combined output of a linear transmission path and a third order distortion generation path, a distortion observation unit that observes distortion in the output of a power amplifier, and a controller are provided, where the controller includes a third order out-of-band distortion compensation coefficient control unit that adjusts coefficients corresponding to an outside of an input signal band among frequency characteristic compensator coefficients on the basis of distortion observed by the distortion observation unit and a third order in-band distortion coefficient control unit that adjusts coefficients corresponding to an inside of the input signal band among frequency characteristic compensator coefficients on the basis of the observed PAPR. | 06-06-2013 |
20130147550 | Power Amplifier Time-Delay Invariant Predistortion Methods and Apparatus - An embodiment of the invention is a time-delay invariant predistortion approach to linearize power amplifiers in wireless RF transmitters. The predistortion architecture is based on the stored-compensation or memory-compensation principle by using a combined time-delay addressing method, and therefore, the architecture has an intrinsic, self-calibrating time-delay compensation function. The predistortion architecture only uses a lookup table to conduct both the correction of non-linear responses of a power amplifier and the compensation of any time-delay effects presented in the same system. Due to the time-delay invariant characteristic, the predistortion design has a wider dynamic range processing advantage for wireless RF signals, and therefore can be implemented in multi-carrier and multi-channel wireless systems. | 06-13-2013 |
20130154733 | METHOD FOR SYNTHESIZING SIGMA-DELTA MODULATOR - A method for synthesizing Sigma-Delta Modulator, which selects at least a system configuration and parameters, substitute a noise transfer formula into said system configuration to obtain coefficients. Using a least-square method to obtain a stability equation, and calculating an ideal performance of said system configuration based on said parameters and stability equation. Substitute the coefficients into non-ideal effect models, and acquire the circuit specification of an operation amplifier in said system configuration in a hierarchic approach to calculate the circuit performance of the operation amplifier. Determine whether said circuit specification of said operation amplifier has a solution based on related specification equation. If an answer is positive, calibrate length and width of transistors in said operation amplifier, until it meets the requirements of said circuit specification. Base on the said transistors to implement Sigma Delta Modulator, the target performance can be achieved from the circuit simulation result. | 06-20-2013 |
20130154734 | Orthogonal Basis Function Set for Digital Predistorter - A predistorter applies a distortion function to an input signal to predistort the input signal. The output of the distortion function is modeled as the sum of the output signals from the orthogonal basis functions weighted by corresponding weighting coefficients. Techniques are described for orthogonalizing the basis function output signals depending on the distribution of the input signal. | 06-20-2013 |
20130187711 | METHOD AND APPARATUS FOR RESOURCE BLOCK BASED TRANSMITTER OPTIMIZATION IN WIRELESS COMMUNICATION DEVICES | 07-25-2013 |
20130194038 | SIGNAL PROCESSING APPARATUS AND AMPLIFICATION APPARATUS - A signal processing apparatus includes a corrector that corrects a digital signal in accordance with a correction value, a converter that converts the digital signal corrected by the corrector into an analog signal, a sample-and-hold unit that holds an instantaneous value of the analog signal that has been obtained by the converter and that has been amplified by an amplifier for a certain frequency that is smaller than twice a maximum frequency of the analog signal, a digitizer that converts the instantaneous value held by the sample-and-hold unit into a digital value when the digitizer received an operation clock having the certain frequency, and an updater that updates, on the basis of the digital value obtained by the digitizer, the correction value of the corrector such that the correction value becomes a correction value that reduces nonlinear distortion in the analog signal amplified by the amplifier. | 08-01-2013 |
20130200950 | PREDISTORTION OF CONCURRENT MULTI-BAND SIGNAL TO COMPENSATE FOR PA NON-LINEARITY - Systems and methods are disclosed for effecting predistortion of a concurrent multi-band signal to compensate for power amplifier non-linearity. In general, the concurrent multi-band signal contains frequency components occupying multiple frequency bands with no frequency components between adjacent frequency bands. In one embodiment, a transmitter includes a power amplifier that amplifies a modulated concurrent multi-band signal to provide an amplified concurrent multi-band signal. A predistortion sub-system effects predistortion of the modulated concurrent multi-band signal prior to amplification in order to compensate for non-linearity of the power amplifier. The predistortion sub-system includes a number of predistorters each providing predistortion for a different one of the frequency bands of the modulated concurrent multi-band signal. At least one of the predistorters provides predistortion for the corresponding frequency band of the modulated concurrent multi-band signal based on carrier frequency information for the modulated concurrent multi-band signal. | 08-08-2013 |
20130200951 | Selective Narrowband Feedback for a Digital Predistorter - A method and apparatus is provided for linearizing the output of a non-linear device, such as a power amplifier. The input signal to the non-linear device is predistorted based on a predistortion model to compensate for distortion introduced by a non-linear device. A wideband feedback signal is generated from the output signal of the non-linear device, and the wideband feedback signal is filtered to generate two or more narrowband distortion signals with predetermined frequencies corresponding to anticipated distortion components in the output signal. Model parameters of the predistortion model are adapted based on the narrowband distortion signals. | 08-08-2013 |
20130214860 | CDMA/OFDM LINEARITY COMPLIANT WIRELESS COMMUNICATION AMPLIFIER - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 08-22-2013 |
20130214861 | BASEBAND-DERIVED RF DIGITAL PREDISTORTION - A baseband-derived RF predistortion system using a lookup table having coefficients extracted at baseband and then applied at RF by means of a vector modulator. The architecture combines the narrowband advantage of envelope predistortion with the accuracy of baseband predistortion, and including compensation for memory effects. A polynomial-based alternative is also described. | 08-22-2013 |
20130222059 | FIR/IIR FILTER PREDISTORTER FOR POWER AMPLIFIERS EXHIBITING SHORT-TERM AND/OR LONG-TERM MEMORY EFFECTS - The present disclosure generally relates to predistortion that compensates for non-linearity of a power amplifier as well as short-term and long-term memory effects of the power amplifier. In one embodiment, a transmitter includes a power amplifier that amplifies a power amplifier input signal to provide a power amplifier output signal, a predistortion sub-system that effects predistortion of the power amplifier input signal to compensate for non-linearity of the power amplifier and memory effects of the power amplifier, and a adaptation sub-system that adaptively configures the predistortion sub-system. The predistortion sub-system includes a memory-less predistortion component that compensates for the non-linearity of the power amplifier, a Finite Impulse Response (FIR) filter that compensates for short-term memory effects of the power amplifier, and an Infinite Impulse Response (IIR) filter that compensates for long-term memory effects of the power amplifier. | 08-29-2013 |
20130241645 | MULTI-LAYER MEMORY STRUCTURE FOR BEHAVIORAL MODELING IN A PRE-DISTORTER - A method and system for modeling distortion of a non-linear electronic device are disclosed. According to one aspect, the invention provides a layered memory structure that includes a plurality of memory structure layers. Each memory structure layer has an input to receive an input signal and has a memory function. Each memory function has at least one delay element that provides a pre-determined delay of the input signal of the memory structure layer. The pre-determined delay is different for each of at least two memory structure layers and is based at least in part on an evaluation period corresponding to the memory structure layer. | 09-19-2013 |
20130241646 | Dual Loop Adaptation Digital Predistortion Architecture for Power Amplifiers - One or more embodiments of a method and apparatus taught herein provide a predistortion system to compensate for the non-linearity of a power amplifier. The system includes an outer predistorter, an inner predistorter, and a first adaptation circuit. The predistorter predistorts an input signal to generate a first output signal, and uses a first memory model that models power amplifier memory effects within a first range of time constants. The inner predistorter predistorts the first output signal to generate a second output signal, and uses a second memory model that models power amplifier memory effects within a second range of time constants that is greater than the first range of time constants. The second output signal is provided as an input to the power amplifier, and the first adaptation circuit adapts the outer predistorter responsive to feedback from the power amplifier. | 09-19-2013 |
20130249631 | MEMORY STRUCTURE HAVING TAPS AND NON-UNITARY DELAYS BETWEEN TAPS - A method and apparatus for memory modeling in a pre-distortion architecture are disclosed. In one embodiment, a memory model has a plurality of branches. Each branch receives a different output basis function signal. Each branch includes at least one delay element. Each delay element causes a pre-determined delay of the output basis function signal received by the branch. The amount of a pre-determined delay is different for each of at least two branches. | 09-26-2013 |
20130257529 | CIRCUITRY FOR REDUCING POWER CONSUMPTION - Circuitry for reducing power consumption is described. The circuitry includes a power amplifier. The circuitry also includes a predistorter coupled to the power amplifier. The circuitry further includes a power supply coupled to the power amplifier. The circuitry additionally includes a controller coupled to the power amplifier, to the predistorter and to the power supply. The controller captures a transmit signal and a feedback signal concurrently and determines a minimum bias voltage from a set of voltages and a predistortion that enable the power amplifier to produce an amplified transmit signal in accordance with a requirement. | 10-03-2013 |
20130257530 | Pre-Distortion for a Radio Frequency Power Amplifier - Coefficients of a pre-distorter are determined for distortion correction of a signal amplified by a radio frequency amplifier by sampling the signal at the pre-distorter input to generate a plurality of input samples and sampling the signal at the amplifier output to generate a plurality of output samples, each of the output samples corresponding to one of the input samples, calculating a figure of merit for one or more of the input samples on the basis of the one or more input samples, selectively updating a previously selected set of input samples with the one or more input samples on the basis of the calculated figure of merit, whereby to generate an updated selected set and determining the coefficients of the pre-distorter on the basis of the input samples in the updated selected set and the corresponding output samples. | 10-03-2013 |
20130257531 | AMPLIFYING DEVICE AND METHOD FOR CONTROLLING THE SAME - It is difficult to realize the low distortion characteristics and the highly-efficient operation of the amplifying device simultaneously, therefore, an amplifying device according to an exemplary aspect of the invention includes a first pre-distorter unit outputting a modulated signal obtained by adding a phase compensation amount and an amplitude adjustment amount to an input signal; a power amplifier inputting the modulated signal and outputting an output signal obtained by amplifying the modulated signal; a power supply voltage modulation unit modulating a power supply voltage of the power amplifier; a second pre-distorter unit controlling the power supply voltage modulation unit on the basis of amplitude information on the input signal; and a control unit controlling an operation of the first pre-distorter unit and the second pre-distorter unit; wherein the control unit includes a phase control unit controlling the phase compensation amount by using a phase coefficient, a first amplitude control unit controlling the amplitude adjustment amount by using a first amplitude coefficient, and a second amplitude control unit controlling the operation of the second pre-distorter unit by using a second amplitude coefficient; and wherein the first amplitude control unit cooperates with the second amplitude control unit so that an amplitude amplification factor may become constant which is a ratio of an amplitude of the output signal to an amplitude of the input signal. | 10-03-2013 |
20130271212 | Digital Predistorter (DPD) Structure Based On Dynamic Deviation Reduction (DDR)-Based Volterra Series - The present invention provides a method an apparatus for predistorting an input signal to compensate for non-linearities in an electronic device that operates on the input signal. The invention may be used, for example, to digitally predistort an input signal for a power amplifier in a wireless communication device. The predistorter uses a polynomial approach based on the well-known Volterra series to model the distortion function. A dynamic deviation reduction technique is used to reduce the number of terms in the distortion model and to facilitate implementation. The approach described herein eliminates square functions present in prior art designs and can be implemented using CORDIC circuits. | 10-17-2013 |
20130271213 | SIGNAL PROCESSING CIRCUIT WITH CIRCUIT INDUCED NOISE CANCELLATION - A signal processing circuit with noise cancellation includes an impedance matching unit and a transconductance stage. The impedance matching unit is disposed at a first path, and arranged to provide input impedance matching, wherein the impedance matching unit is a bilateral element, and the first path is coupled between a signal input port and a signal output port. The transconductance stage is disposed at a second path, and arranged to guide circuit introduced noise to the signal output port for noise cancellation at the signal output port, wherein the second path is coupled between the signal input port and the signal output port. | 10-17-2013 |
20130285742 | Multi-Dimensional Volterra Series Transmitter Linearization - A radio transmission system comprising: a first Volterra Engine (VE) linearizer; a second VE linearizer coupled to the first VE linearizer; and a power amplifier (PA) coupled to at least one of the VE linearizers. Each VE linearizer compensates for a different distortion or nonlinearity aspect of an output signal from the PA. | 10-31-2013 |
20130285743 | AMPLIFIER CIRCUIT AND WIRELESS COMMUNICATION EQUIPMENT - Distortion compensation is performed taking into account a memory effect that occurs in a signal path other than an input-to-output path of an amplifier. An amplifier circuit | 10-31-2013 |
20130307618 | LINEARIZING A POWER AMPLIFIER - A circuit for linearizing a power amplifier. The circuit includes a main signal path comprising a digital-to-analog converter, wherein a main signal is transmitted through the main signal path to said power amplifier; and a digital pre-distortion path disposed outside of the main signal path, wherein the digital pre-distortion path includes a digital pre-distorter for digitally pre-distorting the main signal. | 11-21-2013 |
20130321078 | DISTORTION COMPENSATION APPARATUS AND DISTORTION COMPENSATION METHOD - A distortion compensation apparatus including: a processor configured to generate a pre-distortion signal by compensating an input signal for a distortion based on a distortion compensation coefficient and a plurality of delayed signals obtained by delaying the input signal by a plurality of amounts of delay, and an amplifier configured to generate an amplified signal by amplifying the pre-distortion signal, wherein the processor calculates the distortion compensation coefficient based on the input signal, the pre-distortion signal, and the amplified signal, and calculates the plurality of amounts of delay based on the amplified signal. | 12-05-2013 |
20130328627 | Impedance Bootstrap Circuit for an Interface of a Monitoring Device - An interface for receiving electrical signals representative of a condition of a patient and for conveying representations of the electrical signals to a processing system. The interface includes at least one amplifier circuit configured to alter an amplitude of the electrical signal, a common-mode cancellation amplifier circuit coupled to the at least one amplifier circuit and configured to reduce common-mode signal noise in the electrical signals, and a bootstrap circuit coupled to the at least one amplifier circuit and configured to increase an effective input impedance at an input of the at least one amplifier circuit. | 12-12-2013 |
20130342271 | LINEARIZATION OF POWER AMPLIFIERS THROUGH DIGITAL IN-BAND PREDISTORTION FOLLOWED BY ANALOG PREDISTORTION - A system for implementing linearization of a radio frequency (RF) power amplifier (PA) in a base station, as well as various component circuitry for implementing said system. By means of a smart partitioning of the signal processing for predistortion between the analog domain and the digital domain, a more linear relationship between the digital input data and the output RF signal is achieved. Linearization of the PA's output signal is obtained using a mixed-signal apparatus. The digital baseband signal enters the RF signal source. The RF signal source comprises an in-band predistortion circuit, a micro-controller and digital modulator. The output of the digital modulator is an RF signal that enters the PA module. The PA module is composed of the PA and the RF power amplifier linearizer (RFPAL). The RFPAL comprises an RF predistortion circuit, and RF signal analyzer and a microcontroller. In addition, a backward data interface connects the RF signal source with the RFPAL. | 12-26-2013 |
20140009228 | PRE-DISTORTION FOR FAST POWER TRANSIENT WAVEFORMS - An apparatus and a method select and use parameter values for an RF power amplifier linearizer to pre-distort the input signals of a power amplifier, so as to achieve a linear output response in the power amplifier. The apparatus and the method select from a number of sets of parameter values, each set of parameter values corresponding to a different output power range of the power amplifier. The set of parameters include a coefficient vector tailored for the particular output power range for that set. The power amplifier input power is repeatedly measured and filtered at various time intervals. The input power measurements may be filtered by a fast attack/slow decay filter, which follows the peaks of the measurements under operation of the fast attack portion of the filter and provides a low variance during operation of the slow decay portion of the filter. | 01-09-2014 |
20140009229 | INTEGRATED SIGNAL ANALYZER FOR ADAPTIVE CONTROL OF MIXED-SIGNAL INTEGRATED CIRCUITS - A mixed-signal adaptive integrated circuit may comprise a primary function circuit, a digitally controlled analog sub-system cooperatively connected with the primary function circuit, and an on-chip signal analyzer. The on-chip signal analyzer may be arranged to analyze RF signals. The signal analyzer may comprise at least one multiplexor for selecting selected RF signals for comparison and analysis, and may comprise a digital signal processor (DSP) for analyzing the selected RF signals and adjusting at least one operational parameter of the digital controlled analog sub-system responsive to the analysis. | 01-09-2014 |
20140028392 | PRE-DISTORTION IN RF PATH IN COMBINATION WITH SHAPING TABLE IN ENVELOPE PATH FOR ENVELOPE TRACKING AMPLIFIER - There is disclosed a method of controlling an envelope tracking amplification stage comprising an envelope modulated power supply, the method comprising: determining a shaping function to be applied to an envelope signal for controlling the envelope modulated power supply in dependence on a system linearity objective in a region of operation of the amplifier in which the output power of the amplifier is dependent upon the supply voltage; and determining a pre-distortion function to be applied to an input signal to be amplified in dependence on a further linearity objective of the system, in a region of operation of the amplifier in which the output of the amplifier is dependent upon the input power to the amplifier. | 01-30-2014 |
20140118066 | LOW-COST DIGITAL PREDISTORTION APPARATUS AND METHOD USING ENVELOPE DETECTION FEEDBACK - Disclosed herein is a low-cost digital predistortion apparatus using envelope detection feedback. The low-cost digital predistortion apparatus includes a digital predistortion unit and an envelope detection feedback unit. The digital predistortion unit converts the output of a predistorter into analog signals, frequency-modulates the analog signals into a pass band signal, and amplifies the frequency-modulated signal via a power amplifier. The envelope detection feedback unit converts the difference between the input and output of the power amplifier of the digital predistortion unit and the output of the power amplifier into baseband signals, respectively, converts the baseband signals into digital signals, estimates the nonlinear distortion characteristic output of the power amplifier, calculates a predistortion parameter that is used to compensate for the estimated nonlinear distortion characteristic output of the power amplifier. | 05-01-2014 |
20140125410 | DIGITAL POLAR AND ZVS CONTOUR BASED HYBRID POWER AMPLIFIER - A power amplifier (PA) which improves dynamic range of previous ZVS contour-based power amplifier architectures is presented. The inventive circuit combines ZVS contour-based power amplification with a current mode digital-to-analog converter (DAC) based digital polar power amplifier. The inventive elements interoperate to provide high efficiency even at large peak power back-off levels and increased dynamic range. The invention is particularly well-suited for use in modulation schemes (e.g., WLAN/LTE/WIMAX) having large peak-to-average output power ratios. Utilizing the inventive PA in generating modulation in these systems can increase RF transmitter efficiency of by approximately two-fold. | 05-08-2014 |
20140132346 | METHOD AND SYSTEM FOR COMPENSATING FOR ESTIMATED DISTORTION IN A TRANSMITTER BY UTILIZING A DIGITAL PREDISTORTION SCHEME WITH A SINGLE FEEDBACK MIXER - Aspects of a method and system for compensating for estimated distortion in a transmitter by utilizing a digital predistortion scheme with a single feedback mixer are presented. Aspects of the system may include at least one circuit that enables generation of an output signal in response to one or more generated input signals. A feedback signal may be generated within a single feedback mixer circuit that may perform a frequency mix-down operation on the generated output signal. The generated feedback signal may be inserted at one or more insertion points in a receiver. Each of the insertion points may be located between a mixer stage of the receiver, and one or more circuits that generate a baseband signal based on the generated feedback signal. | 05-15-2014 |
20140139286 | SYSTEMS AND METHODS FOR BAND-LIMITED ADAPTATION FOR PA LINEARIZATION - Systems and methods are disclosed for providing band-limited power amplifier linearization. In one embodiment, a system includes a power amplifier configured to amplify a power amplifier input signal to provide a power amplifier output signal and a digital predistortion system configured to compensate for up to a predefined maximum order of non-linearity of the power amplifier. The digital predistortion system includes a band-limited adaptation subsystem. As compared to conventional adaptation subsystems, the band-limited adaptation subsystem is significantly less complex and consumes less power. | 05-22-2014 |
20140139287 | DISTORTION COMPENSATING APPARATUS, TRANSMITTER, DISTORTION COMPENSATING METHOD, AND TRANSFER FUNCTION CALCULATING METHOD - An amplifier module is expressed by a model having a first filter that is a linear time-invariant filter for limiting the bandwidth of an input signal, an amplifier unit that amplifies a signal output from the first filter, and a second filter that is a linear time-invariant filter for limiting the bandwidth of a signal output from the amplifier unit. A memoryless amplifier unit calculates an output from the amplifier module when being memoryless, using AM-to-AM distortion and AM-to-PM distortion of the amplifier unit. A cross-correlation calculating unit calculates a correlation between the signal output from the amplifier module and the output calculated by the memoryless amplifier unit and calculates an estimate of a transfer function of the first filter and the second filter. A distortion compensating unit compensates the input signal based on the estimate of the transfer function and outputs the signal to the amplifier module. | 05-22-2014 |
20140145788 | DISTORTION COMPENSATION DEVICE AND DISTORTION COMPENSATION METHOD - A distortion compensation device includes a storage unit, an address generator, and a distortion compensation processor. The storage unit stores therein a distortion compensation coefficient for compensating distortion generated in an amplifier for amplifying an input signal. The address generator generates a first address based on a power value of the signal at a current time. Furthermore, the address generator delays, every time a new augend is input, the sum of the power value of the signal at the current time and the augend. The address generator generates a second address based on the sum obtained by calculating a new augend, from the delayed sum. The distortion compensation processor acquires a distortion compensation coefficient corresponding to a combination of the first address and the second address from the storage unit and performs distortion compensation processing on the signal by using the acquired distortion compensation coefficient. | 05-29-2014 |
20140159810 | METHOD AND SYSTEM FOR ALIGNING SIGNALS WIDELY SPACED IN FREQUENCY FOR WIDEBAND DIGITAL PREDISTORTION IN WIRELESS COMMUNICATION SYSTEMS - A system for time aligning widely frequency spaced signals includes a digital predistortion (DPD) processor and a power amplifier coupled to the DPD processor and operable to provide a transmit signal at a power amplifier output. The system also includes a feedback loop coupled to the power amplifier output. The feedback loop comprises an adaptive fractional delay filter, a delay estimator coupled to the adaptive fractional delay filter, and a DPD coefficient estimator coupled to the delay estimator | 06-12-2014 |
20140167844 | DISTORTION COMPENSATION DEVICE AND DISTORTION COMPENSATION METHOD - A distortion compensation device includes: a distortion compensator configured to output, to a power amplifier, a predistortion signal obtained by performing distortion compensation processing on a transmission signal by using a distortion compensation coefficient, wherein the distortion compensator limits bands of a reference signal and a feedback signal so that the bands fall in a pass band and updates the distortion compensation coefficient based on an error between the reference signal and the feedback signal, the reference signal corresponding to the predistortion signal, the feedback signal corresponding to an output feedback of the power amplifier. | 06-19-2014 |
20140167845 | CDMA/OFDM LINEARITY COMPLIANT WIRELESS COMMUNICATION AMPLIFIER - A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available. | 06-19-2014 |
20140184327 | METHOD FOR IMPLEMENTING COMPENSATION FILTER AND APPARATUS FOR SIGNAL BANDWIDTH COMPENSATION - Embodiments of the present invention disclose a method for implementing a compensation filter and an apparatus for signal bandwidth compensation. The apparatus includes: a digital predistortion filtering unit, a compensation filter, a conversion unit, and a power amplifier; where the digital predistortion filtering unit receives an original signal, performs predistortion processing on the original signal; the compensation filter receives the predistortion signal, compensates for distortion caused during a process of transmitting the predistortion signal to the power amplifier, and outputs a compensated predistortion signal to the conversion unit; the conversion unit receives the compensated predistortion signal, converts the compensated predistortion signal into an analog signal, performs frequency mixing processing, and outputs a predistortion signal experiencing the frequency mixing to the power amplifier; the power amplifier receives the predistortion signal experiencing the frequency mixing, amplifies the predistortion signal experiencing the frequency mixing, and outputs an amplified signal. | 07-03-2014 |
20140191798 | TRANSMISSION SIGNAL POWER CONTROL APPARATUS, COMMUNICATION APPARATUS AND PREDISTORTION COEFFICIENT UPDATING METHOD - A transmission signal power control apparatus includes a power amplifier model unit which generates a learning digital signal by multiplying part of a predistortion signal by model coefficients which tentatively represent the input-output characteristics of a power amplifier, and an adaptive low-pass filter which generates a pseudo feedback signal by attenuating the high frequency components of the learning digital signal by multiplying the learning digital signal by weighting coefficients. Then, the power amplifier model unit updates the model coefficients such that the error between the feedback signal whose the high frequency components are attenuated by the low-pass filter and which is digitized, and the pseudo feedback signal is minimized, and the adaptive low-pass filter updates the weighting coefficients such that the error is minimized. | 07-10-2014 |
20140191799 | PREDISTORTER AND PREDISTORTER CONTROL METHOD - In a predistorter that can compensate an intermodulation distortion component generated in a power amplifier even when employing carrier aggregation, a linear transmission path delays and transmits an input signal. Signal generation units generate individual carrier distortion signals for respective carriers included in an input signal to output an individual carrier distortion compensation signal. A sub-signal generation unit generates a carrier inter-modulation distortion signal from the input signal and the individual carrier distortion signal and outputs a carrier inter-modulation distortion compensation signal. A signal divider divides the input signal among the linear transmission path, the signal generation units, and the sub-signal generation unit. A signal combiner combines the individual carrier distortion compensation signal and the carrier inter-modulation distortion compensation signal to generate an output signal to an amplifier. | 07-10-2014 |
20140197885 | AMPLIFYING DEVICE, DISTORTION COMPENSATING DEVICE, AND AMPLIFYING METHOD - An amplifying device including: a first amplifier configured to generate a first output signal by amplifying an input signal, a second amplifier configured to generate a second output signal by amplifying the first output signal, and a processor configured to perform a first compensation by compensating a distortion for the second amplifier in accordance with the first output signal and the second output signal. | 07-17-2014 |
20140218107 | METHOD AND APPARATUS FOR APPLYING PREDISTORTION TO AN INPUT SIGNAL FOR A NONLINEAR POWER AMPLIFIER - Aspects disclosed herein relate to providing an efficiently predistorted input signal to a high-efficiency PA. A wireless communications device may be include a power amplifier and a processor that is associated with a predistortion module. In an aspect, the processor may be a modem, a RF chip, etc. In one example, the pre-distortion module may be configured to receive an input signal and a supply voltage associated with the input signal. The predistortion module may be further configured to apply predistortion to the input signal using a linear manipulation associated with the predistortion lookup table. In an aspect, the linear manipulation may adjust the input signal based on one or more non-linear device characteristics associated with the supply voltage. | 08-07-2014 |
20140218108 | TIMING ALIGNMENT FOR POWER AMPLIFIER - There is described a method of controlling signal alignment in a power amplifier, comprising: receiving an input signal to be amplified; receiving a supply voltage for the power amplifier, the supply voltage being derived in dependence on the signal to be amplified; amplifying the input signal to produce an output signal; comparing the output signal with a plurality of distorted versions of the input signal, each distorted version of the input signal being associated with a different time delay value; and adjusting the timing of either the input signal or the supply voltage by an amount in dependence on a time delay value determined to be associated with a distorted version of the input signal which most closely matches the output signal. | 08-07-2014 |
20140266431 | UNDER-SAMPLING DIGITAL PRE-DISTORTION ARCHITECTURE - A amplifier system may include a predistorter receiving an input signal to generate a predistortion signal, a first converter receiving the predistortion signal to generate a preamplified signal, a power amplifier receiving the preamplified signal to generate an output signal based on the preamplified signal and the input signal, and a second converter sampling the output signal to generate a feedback signal. The power amplifier may produce a distortion signal at a first frequency, the second converter may sample the output signal using a timing signal with a second frequency that is lower than the first frequency to generate the feedback signal, and the predistorter, based upon the feedback signal, may predistort the predistortion signal to reduce the distortion signal at the first frequency. | 09-18-2014 |
20140266432 | AMPLIFIER PHASE DISTORTION CORRECTION BASED ON AMPLITUDE DISTORTION MEASUREMENT - This application discloses correction circuitry for correcting a phase distortion in an amplification circuit by measuring an amplitude distortion and controlling a phase shifting component based upon the measured amplitude distortion. In one embodiment, a first amplitude distortion sensor is coupled to a first node of an amplification circuit, and a first phase shifter is coupled to a second node of the amplification circuit. Additionally, a first control circuit is coupled to the first amplitude sensor and to the first phase shifter. The first control circuit is configured to correlate a first amplitude distortion measured by the first amplitude distortion sensor to a first inferred phase distortion, and to generate a first phase correction signal based upon the first inferred phase distortion, and is configured to send the first phase correction signal towards the first phase shifter. | 09-18-2014 |
20140292403 | POWER AMPLIFIER SIGNAL COMPENSATION - Exemplary embodiments are related to power amplifier power level compensation in a pre-distortion system. A method may include applying digital pre-distortion (DPD) of a power amplifier at a frequency channel, a fixed input power value, and a fixed temperature. The method may also include determining an optimal input power value for the power amplifier in response to a change in at least one of frequency and temperature. | 10-02-2014 |
20140292404 | RADIO-FREQUENCY DEVICE CALIBRATION - Exemplary embodiments are related to method and devices for calibration a radio-frequency (RF) transceiver. A method may include calibrating an RF device by calculating input voltage values and bias voltage values of a power amplifier for each desired output voltage value of the power amplifier to generate a desired compression point. The method may also include applying digital pre-distortion (DPD) values to the input voltage of the power amplifier, and measuring a value of the output voltage after applying the DPD values. | 10-02-2014 |
20140292405 | AMPLIFICATION DEVICE AND AMPLIFICATION METHOD - An amplification device includes: an amplitude adjustment circuit configured to adjust an amplitude level of an input signal so as to keep the amplitude level within a given range; an amplifier configured to amplify the adjusted signal; and a circuitry configured to change an amplitude level of the amplified signal, based on the amplitude level of the input signal and a first distortion compensation corresponding to the amplitude level of the input signal. | 10-02-2014 |
20140292406 | Signal Predistortion for Non-Linear Amplifier - A method, apparatus, and computer program for modeling mathematically an effect of a plurality of factors on signal distortion caused by a non-linear amplifier are provided. First, there is computed a global model which incorporates a combined effect of the plurality of factors on signal distortion caused by the non-linear amplifier. Before applying the pre-distorted transmission signal to the non-linear amplifier, a transmission signal is pre-distorted with coefficients derived from the global model thus compensating for the signal distortion caused by the non-linear amplifier. | 10-02-2014 |
20140306757 | SYSTEMS AND METHODS FOR ADAPTIVE POWER AMPLIFIER LINEARIZATION - An exemplary system comprises a linearizer, a power amplifier, and a feedback block. The linearizer may be configured to use a predistortion control signal to add predistortion to a receive signal to generate a predistorted signal. The power amplifier may be configured to amplify power of the predistorted signal to generate a first amplified signal. The power amplifier may also add high side and low side amplifier distortion to the predistorted signal. The high side and low side amplifier distortion may cancel at least a portion of the predistortion. The feedback block may be configured to capture a feedback signal based on a previous amplified signal from the power amplifier, to determine high side and low side distortion of the captured feedback signal, and to generate the predistortion control signal based on the determined high side and low side distortion. | 10-16-2014 |
20140327481 | DIGITAL HYBRID MODE POWER AMPLIFIER SYSTEM - A RF-digital hybrid mode power amplifier system for achieving high efficiency and high linearity in wideband communication systems is disclosed. The present invention is based on the method of adaptive digital predistortion to linearize a power amplifier in the RF domain. The power amplifier characteristics such as variation of linearity and asymmetric distortion of the amplifier output signal are monitored by the narrowband feedback path and controlled by the adaptation algorithm in a digital module. Therefore, the present invention could compensate the nonlinearities as well as memory effects of the power amplifier systems and also improve performances, in terms of power added efficiency, adjacent channel leakage ratio and peak-to-average power ratio. The present disclosure enables a power amplifier system to be field reconfigurable and support multi-modulation schemes (modulation agnostic), multi-carriers and multi-channels. As a result, the digital hybrid mode power amplifier system is particularly suitable for wireless transmission systems, such as base-stations, repeaters, and indoor signal coverage systems, where baseband I-Q signal information is not readily available. | 11-06-2014 |
20140333376 | SCALABLE DIGITAL PREDISTORTION SYSTEM - The scalable digital predistortion system provides a behavioral model that can be used to model and compensate for the nonlinear distortions of power amplifiers and transmitters. The predistorter and update algorithms make the model/DPD scalable in terms of signal bandwidth and average power, allowing for low complexity update following changes in the signal's bandwidth and/or power level. Experimental validation carried on a 300 Watt Doherty power amplifier shows that the scalable model and the predistorter architecture achieve performance similar to their conventional counterpart. However, the present model/predistorter requires the update of up to 50% fewer coefficients than the conventional model/predistorter. | 11-13-2014 |
20140333377 | CAPTURE BUFFER OF DIGITAL PREDISTORTION SYSTEMS - An improved DPD system includes a predistortion module having at least one predistortion function. The predistortion module is configured to receive and subsequently process a baseband signal. The system also includes a power amplifier configured to receive the processed baseband signal from the predistortion module. The system further includes a model calculator configured to program priorities for predistortion functions so that the processed baseband signal transmitted from the predistortion module corresponds to the transmission power of the power amplifier. The model calculator is further configured to send a trigger signal to indicate when data capture from the power amplifier should begin so as to update the predistortion functions. A trigger module in the system is configured to receive the trigger signal and to initiate data capture from the power amplifier upon receipt of the trigger signal. | 11-13-2014 |
20140347126 | LOW COMPLEXITY DIGITAL PREDISTORTION FOR CONCURRENT MULTI-BAND TRANSMITTERS - Systems and methods are disclosed for digital predistortion for a concurrent multi-band transmitter using a single adaptor and a same set of predistortion coefficients for separate digital predistorters for each band. In one embodiment, the single adaptor is configured to adaptively configure a set of predistortion coefficients based on a memory polynomial digital baseband model of the digital predistorters having a same set of predistortion coefficients for each of the digital predistorters. By using the same set of predistortion coefficients for the separate digital predistorters for each band, a complexity of the digital predistortion is substantially reduced. | 11-27-2014 |
20150015327 | Controller and Method for Controlling a Signal Processor - A controller for controlling a signal processor includes a transformation unit and a control unit. The transformation unit is configured to generate at least one amplitude-modulation-to-phase-modulation-distortion within a signal, output by using the signal processor according to a signal processing, based on generated at least one amplitude-modulation-to-amplitude-modulation-distortion of the signal. The control unit is configured to adjust the signal processing of the signal processor so as to minimize the at least one amplitude-modulation-to-phase-modulation-distortion. | 01-15-2015 |
20150015328 | PRE-DISTORTION METHOD AND ASSOCIATED APPARATUS AND NON-TRANSITORY MACHINE READABLE MEDIUM - A pre-distortion method includes: receiving an input data; and obtaining a pre-distorted output by inputting the input data into a pre-distortion function, wherein the pre-distortion function is determined according to a power amplifier. A pre-distortion apparatus includes a receiver and a pre-distortion unit. The receiver is utilized for receiving an input data. The pre-distortion unit is utilized for obtaining a pre-distorted output by inputting the input data into a pre-distortion function, wherein the pre-distortion function is determined according to a following power amplifier. A non-transitory machine readable medium stores a program code executed for performing steps of the proposed pre-distortion method. | 01-15-2015 |
20150028946 | Amplitude Modulation to Phase Modulation (AMPM) Distortion Compensation - To generate amplitude modulation to phase modulation (AMPM) predistortion data that compensates for phase distortion in a power amplifier of a communication device, a test signal is amplified via the power amplifier. The amplified test signal is combined, by wave superposition, with a reference oscillator signal into a resultant signal. The resultant signal is an outcome of interference between the amplified test signal and the reference oscillator signal. The resultant signal power is measured using envelope information and, from the measurement, a predistortion phase shift is determined that when applied to the test signal maximizes the interference between the amplified test signal and the reference oscillator signal. AMPM predistortion data is generated to correspond with the predistortion phase shift. | 01-29-2015 |
20150028947 | DISTORTION COMPENSATION APPARATUS AND METHOD - A distortion compensation apparatus compensates for non-linear distortion of a power amplifier. The distortion compensation apparatus includes a pre-distorter, a learning unit, and a gain control unit. During training of the pre-distorter, the learning unit repeatedly updates a compensation coefficient on the basis of signals output from the power amplifier. While the training continues after update of the compensation coefficient, the gain control unit performs gain control on a signal before input to the power amplifier. | 01-29-2015 |
20150054579 | SYSTEM AND METHOD FOR FAST POLYNOMIAL PRE-DISTORTION - A system and method for method of pre-distorting a signal applied to a power amplifier to compensate for distortion introduced by the power amplifier at different power settings, comprising pre-distorting the signal according to a pre-distortion polynomial, prior to amplification of the signal by the power amplifier; adaptively estimating and applying pre-distortion polynomial coefficients to the pre-distorter by saving successive iterations of adaptive estimation of the pre-distortion polynomial coefficients; and regularizing estimation of the pre-distortion polynomial coefficients over successive iterations according to a modified objective function that initially constrains growth in the magnitude of the pre-distortion polynomial coefficients and then relaxes the constraint in growth over successive iterations until estimation is reduced to a steady-state least squares estimation. | 02-26-2015 |
20150061762 | DUAL POWER AMPLIFIER LINEARIZER - A circuit in a transmitter with multiple power amplifiers includes multiple individual linearizer circuits each receiving a corresponding input signal and each providing a conditioned input signal to a corresponding power amplifier, The linearizer circuit each include: (a) a pre-distortion circuit receiving (i) the corresponding input signal and (ii) the output signal of a corresponding power amplifier, and providing a pre-distortion signal; (b) a cancelation circuit receiving an interfering signal and providing a cancelation signal; and (c) a combination circuit that combines the cancelation signal and the pre-distortion signal to provide a conditioned input signal to the corresponding power amplifier. | 03-05-2015 |
20150070089 | ADAPTIVE NONLINEAR MODEL LEARNING - In accordance with an example implementation of this disclosure, a receiver may comprise a signal reconstruction circuit and a nonlinearity modeling circuit. The nonlinearity modeling circuit may be operable to generate a look-up table (LUT)-based model of nonlinear distortion present in a received signal. An entry of the LUT may comprise a signal power parameter value and a distortion parameter value. The signal reconstruction circuit may be operable to generate one or more candidates for a transmitted signal corresponding to the received signal. The signal reconstruction circuit may be operable to distort the one or more candidates according to the model, the distortion resulting in one or more reconstructed signals. The signal reconstruction circuit may be operable to decide a best one of the candidates based on the one or more reconstructed signals. | 03-12-2015 |
20150077179 | DISTORTION COMPENSATION APPARATUS, TRANSMISSION APPARATUS, AND DISTORTION COMPENSATION METHOD - A distortion compensation apparatus including: a memory configured to store a plurality of distortion compensation coefficients for compensating distortion to an input signal amplified by an amplifier, each of the plurality of distortion compensation coefficients being associated with a different combination of two addresses, and a processor configured to receive temperature information associated with a temperature of the amplifier, generate a first address based on the input signal at a first time, generate a second address based on an average of the input signal during a previous period preceding the first time, the average being calculated based on the temperature information, select a distortion compensation coefficient from the plurality of distortion compensation coefficients based on the first address and the second address, and compensate distortion to the input signal based on the selected distortion compensation coefficient. | 03-19-2015 |
20150077180 | DISTORTION COMPENSATION APPARATUS AND DISTORTION COMPENSATION METHOD - A distortion compensation apparatus includes: a storage unit that stores a distortion compensation coefficient; a distortion-compensation-coefficient selecting unit that takes a logarithm of power of an input signal and exponentiates a value obtained by taking the logarithm, and that selects a distortion compensation coefficient that is stored in the storage unit according to a value obtained by the exponentiating; a distortion-compensation processing unit that acquires the selected distortion compensation coefficient from the storage unit, and that performs distortion compensation processing on the input signal to the distortion-compensation-coefficient selecting unit using the acquired distortion compensation coefficient; an amplifier that amplifies the signal subjected to the distortion compensation processing; and a distortion-compensation-coefficient updating unit that updates the distortion compensation coefficient stored in the storage unit based on the amplified signal and the input signal to the distortion-compensation-coefficient selecting unit. | 03-19-2015 |
20150091643 | Using Fractional Delay Computations to Improve Intermodulation Performance - Enhancing the intermodulation performance of an RF power amplifier by determining a coarse time delay represented by an integer T1; determining a reference point for a transmitted signal waveform of the RF power amplifier; shifting the waveform by a set of offsets comprising a plurality of non-integer fractional steps from (T1−Xd) to (T1+Xd) where T1 is the integer and Xd is a non-integer fractional step size value for defining fractional steps about the integer T1 such that the non-integer fractional steps progress in a positive direction as well as a negative direction; correlating the transmitted signal waveform with a feedback signal waveform to obtain a respective correlation value for each of corresponding fractional steps; obtaining an accurate fractional delay value by selecting a fractional step having a highest respective correlation value; applying the obtained correct fractional delay value to the transmitted signal waveform to provide a compensated transmitted signal waveform, and combining the compensated transmitted signal waveform with the feedback signal waveform to reduce at least one intermodulation product of the RF power amplifier. | 04-02-2015 |
20150097618 | DISTORTION COMPENSATION APPARATUS AND METHOD THEREFOR - A distortion compensation apparatus includes a pre-distorter, a gain control unit, and a learning unit. The pre-distorter adds distortion according to compensation coefficients to individual input signals prior to the input signals being input to a power amplifier. The gain control unit applies gain control to individual feedback signals fed back from the power amplifier according to a maximum level of the feedback signals within a time frame. The learning unit updates the compensation coefficients used by the pre-distorter, using the feedback signals subjected to the gain control by the gain control unit. | 04-09-2015 |
20150097619 | AMPLIFIER - An amplifier includes two input terminals to receive a differential, two-tone transmission signal; two output terminals; a coil having terminals connected with the input terminals respectively, and a center tap; a first transistor having the gate connected with one terminal of the coil, and the output terminal connected with one output terminal; a second transistor having the gate connected with the other terminal of the coil, end the output terminal connected with the other output terminal; a diode having a terminal connected with the center tap; and a bias circuit connected with the other terminal of the diode to output a gate voltage to turn on the first and second transistors. The diode adjusts the terminal voltage depending on a signal level of a double harmonic wave of the transmission signal supplied to the terminal of the diode from the center tap. | 04-09-2015 |
20150116032 | PRE-DISTORTION BASED POWER CONTROL - An apparatus comprises an amplifier and a pre-distortion circuit coupled to an input of the amplifier. A saturation value of an input signal corresponds to a maximum output power of an output signal of the amplifier. An input target value of the input signal is determined according to the saturation value. The input target value is determined by subtracting an offset from the saturation value or by multiplying a ratio by the saturation value. An average value or an RMS value of the input signal is controlled to be substantially equal to the input target value. A method comprises determining an input target value according to a saturation value, and controlling an input signal according to the input target value. | 04-30-2015 |
20150145595 | SYSTEM LINEARIZATION ASSEMBLY AND METHOD FOR USE IN MODIFYING DISTORTION COMPONENTS - A system linearization assembly generally includes a filter that is coupled to a measuring device. The filter is configured to receive a signal that includes a time varying parameter representing a plurality of frequency components including at least one component caused by non-linear intermodulation distortion, such as an odd-order intermodulation distortion component. The filter is also configured to isolate at least one harmonic of the frequency components with the same order as the component caused by non-linear intermodulation distortion. The measuring device is configured to measure at least one parameter of the isolated harmonic. The system linearization assembly also includes a controller coupled to the measuring device. The controller is configured to modify, for example by minimizing, the signal from the determined measurement to facilitate a modification, such as a reduction, of the component caused by non-linear intermodulation distortion. | 05-28-2015 |
20150349725 | DISTORTION-COMPENSATION DEVICE AND DISTORTION-COMPENSATION METHOD - Disclosed is a distortion-compensation apparatus that can reduce the storage space for storing coefficients required for distortion-compensation calculation, and can accurately execute distortion compensation. Distortion-compensation apparatus ( | 12-03-2015 |
20150365056 | DISTORTION COMPENSATION APPARATUS AND DISTORTION COMPENSATION METHOD - A distortion compensation apparatus includes a calculation unit that acquires, from calculation performed by using a factor and an output signal from the amplifier, a distortion component that is associated with the distortion generated in the amplifier, and a comparing unit that compares a signal that is obtained by giving the distortion component acquired by the calculation unit to an output signal output from the amplifier, with an input signal input to the amplifier, to which a distortion component is previously given. The calculation unit adjusts, on the basis of a comparison result obtained by the comparing unit, the factor that is used for the calculation. | 12-17-2015 |
20160065146 | AMPLIFICATION PHASE CORRECTION IN A PULSE BURST - An apparatus having an amplifier and a correction circuit is disclosed. The amplifier may be configured to amplify an intermediate signal to generate an output signal. The amplifier is generally a microwave frequency power amplifier. The correction circuit may be configured to (i) generate a control signal based on a plurality of characteristics of the amplifier, and (ii) adjust a plurality of phases of a plurality of pulses in a pulse burst to generate the intermediate signal. The adjusting may be in response to the control signal. The pulse burst is generally received in an input signal. The phases of the pulses as adjusted in the intermediate signal generally cancel a plurality of phase errors induced by the amplifier in the pulses. | 03-03-2016 |
20160079932 | APPARATUS AND METHOD FOR DIGITAL PRE-DISTORTION IN WIRELESS COMMUNICATION SYSTEM - Provided is a Digital Pre-Distortion (DPD) apparatus and method for processing a signal that is input to a power amplifier in a wireless communication system. The DPD apparatus includes a DPD unit configured to pre-distort an input signal that is input to the power amplifier, using DPD information; and a signal processor configured to capture signals for estimation of the DPD information from each of an input terminal and an output terminal of the power amplifier, detect peak signals of the captured signals, separate the detected peak signals into a plurality of intervals depending on a power level, separately store the detected peak signals, estimate the DPD information using the peak signals stored for each interval, and provide the estimated DPD information to the DPD unit. | 03-17-2016 |
20160126903 | WEIGHTED MEMORY POLYNOMIAL METHOD AND SYSTEM FOR POWER AMPLIFIERS PREDISTORTION - A system and method for linearizing a power amplifier using digital predistortion technique is provided including processing circuitry, the processing circuitry configured to apply a digital predistortion function based on a weighted static polynomial function, a weighted dynamic polynomial function and a threshold parameter which splits the nonlinear transfer characteristics of the device under test into a region where the static nonlinearity predominates and a region where the dynamic distortions predominate. | 05-05-2016 |
20160134248 | DISTORTION COMPENSATION APPARATUS AND WIRELESS COMMUNICATION APPARATUS - Distortion is effectively reduced in a wide frequency band of an output signal from an amplifier. A distortion compensation apparatus includes: a distortion compensation processing section that performs a distortion compensation process on an input signal to the amplifier, based on a first amplifier model of the amplifier, and output a compensated signal; a signal generation section that receives the compensated signal and a first digital monitor signal, and generates a second digital monitor signal; and an estimation section that estimates the first amplifier model, based on the compensated signal and the second digital monitor signal. The first digital monitor signal is a signal generated by subjecting an analog monitor signal obtained by monitoring an output signal from the amplifier, to analog-to-digital conversion. A monitor band of the first digital monitor signal is narrower than a frequency band of the compensated signal. A frequency band of the second digital monitor signal is wider than the monitor band of the first digital monitor signal, and includes signal components obtained by restoring signal components outside the monitor band, among signal components included in the analog monitor signal. The signal generation section restores the signal components outside the monitor band among the signal components included in the analog monitor signal, based on the compensated signal and the first digital monitor signal. | 05-12-2016 |
20180026587 | Stabilization of Direct Learning Algorithm for Wideband Signals | 01-25-2018 |
20190149103 | Stabilization of Direct Learning Algorithm for Wideband Signals | 05-16-2019 |