Patent application number | Description | Published |
20090009243 | Methods and Apparatus for Controlling Leakage and Power Dissipation in Radio Frequency Power Amplifiers - A radio frequency power amplifier (RF PA) apparatus includes an RF PA and a waveform converter. The waveform converter is configured to receive a sinusoidal RF signal and generate a nonsinusoidal RF signal, which is used to drive an active device (e.g., a field effect transistor (FET) or bipolar junction transistor (BJT)) of the RF PA. The nonsinusoidal RF signal, which may comprise a square wave or a substantially-square wave signal, has signal characteristics that result in less leakage through the active device's input-output parasitic capacitance, compared to the leakage that would result if the sinusoidal RF signal was used to drive the active device. The leakage control methods and apparatus of the present invention may be advantageously employed in a variety of applications including, for example, RF polar transmitters. | 01-08-2009 |
20090011730 | Methods and Apparatus for Controlling Power in a Polar Modulation Transmitter - A power amplifier of a polar transmitter having separate amplitude and phase paths is configured so that its output power is controlled by power control circuitry disposed in both the amplitude and phase paths of the transmitter. Coarse power control is provided by coarse power control circuitry configured in the phase path. Fine power control is performed by digital power control circuitry configured in the amplitude path. The combined coarse power control circuitry in the phase path and digital power control circuitry in the amplitude path allows the output power of the power amplifier to be controlled at the accuracy and resolution required by wireless communications standards such as, for example, the W-CDMA standard. | 01-08-2009 |
20090093223 | METHODS AND APPARATUS FOR REDUCING RADIATED FIELD FEEDBACK IN RADIO FREQUENCY TRANSMITTERS - Methods and apparatus for reducing radiated field feedback in radio frequency (RF) transmitters. An exemplary RF transmitter includes a power amplifier (PA) and a low-field oscillator (LFO) that are co-located, either on a common module or integrated in the same integrated circuit chip. By using an LFO for the transmitter's local oscillator, radiated field feedback from the PA to the LFO is substantially reduced. In addition to, or instead of using an LFO to reduce radiated field feedback, the LFO or a voltage controlled oscillator (VCO) may be configured to operate at either a harmonic or a non-integer multiple of the transmitter's output signal frequency. Using an LFO or VCO and/or operating the oscillator at a harmonic or a non-integer multiple of the radio system output signal frequency reduces the degree by which electromagnetic fields generated by the radio system's PA and antenna interfere with electromagnetic fields generated by the LFO or VCO, thereby allowing the LFO or VCO to be co-located with or integrated in the same integrated circuit chip as the radio system's PA. | 04-09-2009 |
20090111397 | POLAR MODULATION TRANSMITTER WITH ENVELOPE MODULATOR PATH SWITCHING - Methods and apparatus for controlling power in a polar modulation transmitter. An exemplary polar modulation transmitter includes a radio frequency power amplifier (RF PA), a phase path having circuitry operable to generate a constant amplitude phase modulated signal, and an amplitude path including an envelope modulator circuit having first and second envelope modulation paths. The RF phase modulated signal is applied to an RF input of the RF PA, while an envelope modulated power supply signal generated by a selected one of the first and second envelope modulation paths is coupled to a power supply input of the RF PA. The second envelope modulation path is selected during times when the power required by the RF PA is below some predetermined power level. During times when the RF PA requires power above the predetermined power level, the first envelope modulation path is selected. | 04-30-2009 |
20090129508 | QUADRATURE ALIGNMENT IN COMMUNICATIONS RECEIVERS - The present invention, generally speaking, takes advantage of the properties of quadrature signals to achieve precise quadrature alignment in a simple fashion. In particular, the expectation of the product of quadrature signals is zero. In accordance with the teachings of the invention, a phase error detection network therefore operates by multiplying the received quadrature signals and low-pass filtering the product to produce an error signal. When the signals are in precise quadrature relationship, the error signal will be zero. Real-time feedback control may be used to drive the error to zero. In accordance with another aspect of the invention, a variable phase shift network is achieved using a dual delay line. The difference in delay between the two delay lines is adjusted in response to the error signal to obtain precise quadrature alignment. The principles of the invention may be applied in connection with traditional mixer architectures or with switch-mode (e.g., “aliased undersampling”) architectures. | 05-21-2009 |
20090196387 | INSTANT-ACQUISITION CLOCK AND DATA RECOVERY SYSTEMS AND METHODS FOR SERIAL COMMUNICATIONS LINKS - Methods and systems for recovering clock and data in data streams communicated over serial communications links. An exemplary serial communications receiver system includes a line receiver configured to receive a data stream from a serial communications link and an instant-acquisition clock and data recovery circuit coupled to the line receiver. The instant-acquisition clock and data recovery circuit includes a time interval detector and a sampling clock selector. The time interval detector is operable to sample the data stream received by the line receiver according to a multi-phase set of sampling clocks. The sampling clock selector is operable to designate one of the sampling clocks of the multi-phase set of sampling clocks as a recovered clock, based on a data transition in the received data stream detected by the time interval detector. The clock selector is configured to designate the sampling clock as the recovered clock independent of data transitions in the data stream that may have occurred prior to the data transition detected by the time interval detector. | 08-06-2009 |
20090207941 | Delay-Based Modulation of RF Communications Signals - An apparatus for providing an angle modulated signal includes a tunable oscillator circuit, a variable time delay circuit, and an optional scaling and delay control apparatus. The tunable oscillator circuit generates an oscillatory signal having a predetermined frequency. The variable time delay circuit operates to delay the oscillatory signal in accordance with time varying changes in an angle control signal, thereby producing the desired angle modulated signal. The scaling and delay control apparatus is configured to scale the angle control signal to account for frequency dependent phase delays of the oscillatory signal through the variable time delay circuit. The methods and apparatus of the present invention may be advantageously used in RF transmitters and receivers, such as in a polar transmitter, where the oscillatory signal generated by the tunable oscillator apparatus serves as a carrier signal, and the angle control signal used to control the delay of the variable time delay circuit comprises a phase modulation signal from the phase path of the polar transmitter. | 08-20-2009 |
20090233644 | MULTIPLE CARRIER RADIO SYSTEMS AND METHODS EMPLOYING POLAR ACTIVE ANTENNA ELEMENTS - A multiple carrier radio system includes a baseband subsystem and a plurality of polar modulators. The polar modulators are mounted at antenna locations (e.g., in a base transceiver station (BTS)) above the ground), and are configured to receive modulation signals generated by the baseband subsystem. The plurality of polar modulators generates a plurality of modulated RF carrier signals using the modulation signals. The modulated RF carrier signals are radiated by a corresponding plurality of antenna elements coupled to the plurality of polar modulators. | 09-17-2009 |
20090237157 | POWER AMPLIFIER EDGE EVALUATION-ALTERNATIVE ENVELOPE MODULATOR - A modulator includes a power driver, a power amplifier, and a heterojunction bipolar transistor (HBT) type device. The power driver is for receiving an amplitude modulation signal and for providing a control signal. The power amplifier is for receiving a phase modulation signal, a bias voltage, and the control signal. The power amplifier is for providing a radio frequency signal as an output based on the phase modulation signal, the bias voltage, and the control signal. The switching device is for coupling the power driver to the power amplifier such that the control signal is provided to the power amplifier in a timely manner. | 09-24-2009 |
20090251368 | PHASED ARRAY RECEIVERS AND METHODS EMPLOYING PHASE SHIFTING DOWNCONVERTERS - A phased array receiver includes a plurality of receive paths having a plurality of downconverters, a plurality of digitally controlled local oscillators associated with the plurality of receive paths, and a combiner. In response to a plurality of digital phase control signals, the plurality of digitally controlled local oscillators controls phases of a plurality of local oscillator signals generated by the plurality of digitally controlled local oscillators. The phases of the plurality of local oscillator signals are introduced as phase shifts in a plurality of intermediate frequency signals produced by the plurality of downconverters. The plurality of digitally controlled local oscillators is configured to respond to changes in digital values of the plurality of digital phase control signals to achieve a desired phase relationship among the phases of the intermediate frequency signals. | 10-08-2009 |
20100002807 | Frequency Demodulation with Threshold Extension - A frequency demodulator comprises a frequency discriminator configured to generate a frequency modulation signal from frequency modulated signal, circuitry for generating a phase modulation signal from the frequency modulation signal, and a click reduction signal processing (CRSP) circuit operable to remove noise enhancements from the phase modulation signal caused by clicks. By first converting the frequency modulation signal to a phase modulation signal, noise enhancements caused by clicks are more readily distinguished from other noise in the phase modulation signal. After the noise enhancements have been removed by the CRSP, the frequency modulation is recovered substantially free of clicks. Removal of the clicks results in an improved output signal-to-noise ratio, thereby advantageously extending the onset of the threshold effect. | 01-07-2010 |
20100009641 | DIGITAL RF PHASE CONTROL IN POLAR MODULATION TRANSMITTERS - An exemplary modulator apparatus for a polar modulation transmitter includes a phase difference extractor, a phase modulator, and a coarse phase controller. The phase difference extractor is configured to extract +180° and −180° phase differences represented in a phase-difference modulation signal in a phase modulation path of the polar modulation transmitter, or extract other phase differences exceeding other predetermined phase difference thresholds, to produce a bandwidth-reduced phase-difference modulation signal. The phase modulator includes a controlled oscillator having a tuning port that is modulated by phase differences represented in the bandwidth-reduced phase-difference modulation signal, to produce a phase-modulated RF carrier signal. The coarse phase controller operates to effectuate phase reversals or introduce other coarse phase changes into the phase-modulated RF carrier signal, based on the phase differences extracted from the original phase-difference modulation signal. | 01-14-2010 |
20100124889 | ADAPTIVE DELAY ALIGNMENT IN POLAR TRANSMITTERS - A polar transmitter includes a power amplifier (PA), an amplitude modulation (AM) path including an AM path adjustable delay, an AM path delay measurement circuit, a phase modulation (PM) path including a PM path adjustable delay, and a PM path delay measurement circuit. The AM path delay measurement circuit is configured to measure an AM path delay using waveform correlation, e.g., using peak magnitude events (PMEs) in signals transmitted along the AM path to a power supply port of the PA. The PM path delay measurement circuit is configured to measure a PM path delay using waveform correlation, e.g., using PMEs in signals transmitted along the PM path to a phase-modulated input of the PA. The measured AM and PM path delays are used to adjust the AM and PM path adjustable delays, to reduce the delay mismatch between signals appearing at the power supply and phase-modulated input ports of the polar transmitter's PA. | 05-20-2010 |
20110084703 | Frequency Extension Methods and Apparatus for Low-Frequency Electronic Instrumentation - An electronic measuring system for extending the effective measurement input frequency range of an electronic measuring instrument includes an electronic measuring instrument and a frequency downconverting subsystem, separate from the electronic measuring instrument, having one or more cascaded (i.e., series-connected) downconverting frequency extending units (FEU-Ds). Each FEU-D of the frequency downconverting subsystem includes a downconverting circuit (e.g., a block downconverter) enclosed within a housing. The frequency downconverting subsystem operates to downconvert a test signal from a device under test (DUT) to a downconverted test signal having a frequency within the permissible input frequency range of the measuring instrument, thereby extending the effective measurement input frequency range of the electronic measuring instrument. | 04-14-2011 |
20120081023 | Power Conversion and Control Systems and Methods for Solid-State Lighting - A solid-state lighting system comprises a plurality of light-emitting devices (e.g., light-emitting diodes) and an alternating current to direct current (AC-DC) converter that converts AC power to DC power for powering the plurality of light-emitting devices. The AC-DC converter is configured to perform AC-DC conversion directly, without the need for or use of a bridge rectifier or step-down transformer. According to one aspect of the invention, the light-emitting devices of the solid-state lighting system are autonomous and individually powered by a plurality of DC power supplies generated from the DC power produced by the AC-DC converter. According to another aspect, a plurality of phase-offset dimmer control signals are generated based on waveform distortions in a dimming signal produced by a conventional dimmer switch. The phase-offset dimmer control signals are used to individually control the dimming of the light-emitting devices. | 04-05-2012 |
20120081025 | Power Conversion and Control Systems and Methods for Solid-State Lighting - A solid-state lighting system comprises a plurality of light-emitting devices (e.g., light-emitting diodes) and an alternating current to direct current (AC-DC) converter that converts AC power to DC power for powering the plurality of light-emitting devices. The AC-DC converter is configured to perform AC-DC conversion directly, without the need for or use of a bridge rectifier or step-down transformer. According to one aspect of the invention, the light-emitting devices of the solid-state lighting system are autonomous and individually powered by a plurality of DC power supplies generated from the DC power produced by the AC-DC converter. According to another aspect, a plurality of phase-offset dimmer control signals are generated based on waveform distortions in a dimming signal produced by a conventional dimmer switch. The phase-offset dimmer control signals are used to individually control the dimming of the light-emitting devices. | 04-05-2012 |
20120081035 | Power Conversion and Control Systems and Methods for Solid-State Lighting - A solid-state lighting system comprises a plurality of light-emitting devices (e.g., light-emitting diodes) and an alternating current to direct current (AC-DC) converter that converts AC power to DC power for powering the plurality of light-emitting devices. The AC-DC converter is configured to perform AC-DC conversion directly, without the need for or use of a bridge rectifier or step-down transformer. According to one aspect of the invention, the light-emitting devices of the solid-state lighting system are autonomous and individually powered by a plurality of DC power supplies generated from the DC power produced by the AC-DC converter. According to another aspect, a plurality of phase-offset dimmer control signals are generated based on waveform distortions in a dimming signal produced by a conventional dimmer switch. The phase-offset dimmer control signals are used to individually control the dimming of the light-emitting devices. | 04-05-2012 |
20120126909 | DUTY CYCLE TRANSLATOR METHODS AND APPARATUS - Methods and apparatus for translating duty cycle information in duty-cycle-modulated signals to higher frequencies or higher data rates. An exemplary duty cycle translator includes a duty cycle evaluator, a high-speed digital counter, and a comparator. The duty cycle evaluator generates a first digital number representing a duty cycle of a low-frequency input duty-cycle-modulated (DCM) signal. The comparator compares the first digital number to a second digital number generated by the high-speed digital counter, and generates, based on the comparison, an output DCM signal having a higher frequency or data rate than the frequency or data rate of the low-frequency input DCM signal but a duty cycle that is substantially the same as the duty cycle of the low-frequency input DCM signal. | 05-24-2012 |
20130022149 | COMMUNICATIONS TRANSMITTER HAVING HIGH-EFFICIENCY COMBINATION MODULATOR - A communications transmitter includes a combination modulator and a baseband processor configured to generate amplitude, angle, in-phase and quadrature signals. The combination modulator is configured to modulate in the quadrature domain or the polar domain, depending on an output power level of the transmitter and/or the type of modulation scheme being used. When configured to modulate in the quadrature domain, the baseband processor is configured to generate time-varying in-phase and quadrature modulating signals and time-invariant amplitude and angle signals for the combination modulator. When configured to modulate in the polar domain, the baseband processor is configured to generate time-varying amplitude and angle modulating signals and time-invariant in-phase and quadrature signals for the combination modulator. In another embodiment of the invention, the communications transmitter is configurable to operate in three different operational modes: linear, envelope tracking and switch modes. Which operational mode the communications transmitter is configured to transmit depends on the type of modulation scheme being used and/or the transmitter output power level. | 01-24-2013 |
20130022150 | COMMUNICATIONS TRANSMITTER HAVING HIGH-EFFICIENCY COMBINATION MODULATOR - A communications transmitter includes a combination modulator and a baseband processor configured to generate amplitude, angle, in-phase and quadrature signals. The combination modulator is configured to modulate in the quadrature domain or the polar domain, depending on an output power level of the transmitter and/or the type of modulation scheme being used. When configured to modulate in the quadrature domain, the baseband processor is configured to generate time-varying in-phase and quadrature modulating signals and time-invariant amplitude and angle signals for the combination modulator. When configured to modulate in the polar domain, the baseband processor is configured to generate time-varying amplitude and angle modulating signals and time-invariant in-phase and quadrature signals for the combination modulator. In another embodiment of the invention, the communications transmitter is configurable to operate in three different operational modes: linear, envelope tracking and switch modes. Which operational mode the communications transmitter is configured to transmit depends on the type of modulation scheme being used and/or the transmitter output power level. | 01-24-2013 |
20130022151 | COMMUNICATIONS TRANSMITTER HAVING HIGH-EFFICIENCY COMBINATION MODULATOR - A communications transmitter includes a combination modulator and a baseband processor configured to generate amplitude, angle, in-phase and quadrature signals. The combination modulator is configured to modulate in the quadrature domain or the polar domain, depending on an output power level of the transmitter and/or the type of modulation scheme being used. When configured to modulate in the quadrature domain, the baseband processor is configured to generate time-varying in-phase and quadrature modulating signals and time-invariant amplitude and angle signals for the combination modulator. When configured to modulate in the polar domain, the baseband processor is configured to generate time-varying amplitude and angle modulating signals and time-invariant in-phase and quadrature signals for the combination modulator. In another embodiment of the invention, the communications transmitter is configurable to operate in three different operational modes: linear, envelope tracking and switch modes. Which operational mode the communications transmitter is configured to transmit depends on the type of modulation scheme being used and/or the transmitter output power level. | 01-24-2013 |
20130063220 | Wideband Phase Modulation Methods and Apparatus - A wideband phase modulator comprises a multiphase generator, a phase selector, and a phase adjuster. The wideband phase modulator is configured to receive an N-bit digital phase-modulating signal comprising a timed sequence of N-bit phase-modulating words, where N is a positive integer representing the bit resolution of the N-bit digital phase-modulating signal. The multiphase generator generates a plurality of coarse carrier phases, all having the same carrier frequency but each offset in phase relative to the other. The M most significant bits of the N-bit phase-modulating words are used to form M-bit phase select words that control the output phase of the phase selector. The phase adjuster performs a precision rotation operation, whereby a selected coarse carrier phase is adjusted so that the phase of the resulting final precision phase-modulated signal more closely aligns with a desired precision phase. | 03-14-2013 |
20130113642 | Duty Cycle Translator Methods and Apparatus - Methods and apparatus for translating duty cycle information in duty-cycle-modulated signals to higher frequencies or higher data rates. An exemplary duty cycle translator includes a duty cycle evaluator, a high-speed digital counter, and a comparator. The duty cycle evaluator generates a first digital number representing a duty cycle of a low-frequency input duty-cycle-modulated (DCM) signal. The comparator compares the first digital number to a second digital number generated by the high-speed digital counter, and generates, based on the comparison, an output DCM signal having a higher frequency or data rate than the frequency or data rate of the low-frequency input DCM signal but a duty cycle that is substantially the same as the duty cycle of the low-frequency input DCM signal. | 05-09-2013 |
20130119880 | Power Conversion and Control Systems and Methods for Solid-State Lighting - A solid-state lighting system comprises a plurality of light-emitting devices (e.g., light-emitting diodes) and an alternating current to direct current (AC-DC) converter that converts AC power to DC power for powering the plurality of light-emitting devices. The AC-DC converter is configured to perform AC-DC conversion directly, without the need for or use of a bridge rectifier or step-down transformer. According to one aspect of the invention, the light-emitting devices of the solid-state lighting system are autonomous and individually powered by a plurality of DC power supplies generated from the DC power produced by the AC-DC converter. According to another aspect, a plurality of phase-offset dimmer control signals are generated based on waveform distortions in a dimming signal produced by a conventional dimmer switch. The phase-offset dimmer control signals are used to individually control the dimming of the light-emitting devices. | 05-16-2013 |
20130120190 | PHASED ARRAY TRANSMISSION METHODS AND APPARATUS - A phased array transmitter includes a plurality of vector modulators, an in-phase/quadrature (I/Q) signal generator, and a multiphase generator. The output phases of the plurality of vector modulators, and hence the direction of transmission of the phased array transmitter, are set and controlled by adjusting both the magnitude ratios of I/Q signal pairs generated by the I/Q signal generator and applied to I and Q inputs of the plurality of vector modulators and phases of a plurality of local oscillator (LO) signal phases generated by the multiphase generator and applied to LO inputs of the plurality of vector modulators. Setting and controlling the output phases of the vector modulators by varying both the magnitude ratios of the I/Q signal pairs and the phases of the LO signal phases allows the output phases of the plurality of vector modulators to be more precisely set and controlled than if the output phases were to be set and controlled only through the LO paths or only through the I/Q signal paths of the plurality of vector modulators. | 05-16-2013 |
20130147500 | Frequency Extension Methods and Apparatus for Low-Frequency Electronic Instrumentation - An electronic measuring system for extending the effective measurement input frequency range of an electronic measuring instrument includes an electronic measuring instrument and a plurality of downconverting frequency extenders from which two or more downconverting frequency extenders can be selected and configured in series between a test signal output of a device under test (DUT) and a measuring input of the electronic measuring instrument, to selectively and effectively extend the permissible input frequency range of the electronic measuring instrument. The electronic measuring system may optionally include a plurality of upconverting frequency extenders from which one or more upconverting frequency extenders can be selected to selectively and effectively extend the maximum output frequency range of a signal generator used to generate stimulus signals for the DUT. | 06-13-2013 |
20130234613 | Power Conversion and Control Systems and Methods for Solid-State Lighting - A power conversion and control system suitable for use with solid-state lighting and conventional TRIAC dimmer switching includes an alternating current to direct current (AC-DC) converter configured to convert AC power from the AC mains to DC power and a controller configured to control dimming of a light-emitting load depending on the magnitude of a distorted AC voltage from an external TRIAC dimmer switch relative to the magnitude of the DC voltage Vdc produced by the AC-DC converter. To prevent the TRIAC in the external TRIAC dimmer switch from turning off in situations where the AC-DC converter is disconnected from the AC mains or not drawing any current from the AC mains, the power conversion and control system may further include circuitry that maintains the current through the TRIAC above its minimum holding current. | 09-12-2013 |
20130266089 | Wideband Phase Modulation Methods and Apparatus - A wideband phase modulator comprises a multiphase generator, a phase selector, and a phase adjuster. The wideband phase modulator is configured to receive an N-bit digital phase-modulating signal comprising a timed sequence of N-bit phase-modulating words, where N is a positive integer representing the bit resolution of the N-bit digital phase-modulating signal. The multiphase generator generates a plurality of coarse carrier phases, all having the same carrier frequency but each offset in phase relative to the other. The M most significant bits of the N-bit phase-modulating words are used to form M-bit phase select words that control the output phase of the phase selector. The phase adjuster performs a precision rotation operation, whereby a selected coarse carrier phase is adjusted so that the phase of the resulting final precision phase-modulated signal more closely aligns with a desired precision phase. | 10-10-2013 |
20130336031 | AC/DC Power Conversion Methods and Apparatus - An AC/DC power conversion apparatus comprises an AC/DC converter for converting AC power to DC power for a load and a controller that maintains a power factor of the load as the load varies. The AC/DC converter includes an inductor and a plurality of switches that alternately connects and disconnects the inductor to and from an AC power source, to generate the DC power for the load. The plurality of switches is controlled by a plurality of switch drive signals generated by the controller, based on comparisons of an AC voltage from the AC power source to a DC output voltage produced by the AC/DC converter. To maintain the power factor of the load, the controller is configured to adjust the frequency of the plurality of switch drive signals in response to variations in the load while holding the duty cycles of the switch drive signals constant. | 12-19-2013 |
20140103889 | Rapid-Transition DC-DC Converter - A DC-DC converter for delivering electrical power to a load includes an output filter having an inductor and an output capacitor, a first switch, and a second switch. The first switch is configured to alternately couple and decouple the inductor to and from a DC input voltage as power is being delivered to the load. The second switch is configured to electrically disconnect the output capacitor when the load is removed or deactivated. Disconnecting the output capacitor allows the DC-DC converter to rapidly transition from an operating state to a disabled state, obviating any need to discharge the output capacitor in order to fully disable the DC-DC converter. Residual energy stored in the electric field of the output capacitor and/or the magnetic field of the inductor at the time the load is next reactivated is available to hasten transition back to the operating state. | 04-17-2014 |
20140239833 | Power Conversion and Control Systems and Methods for Solid-State Lighting - A solid-state lighting system comprises a plurality of light-emitting devices (e.g., light-emitting diodes) and an alternating current to direct current (AC-DC) converter that converts AC power to DC power for powering the plurality of light-emitting devices. The AC-DC converter is configured to perform AC-DC conversion directly, without the need for or use of a bridge rectifier or step-down transformer. According to one aspect of the invention, the light-emitting devices of the solid-state lighting system are autonomous and individually powered by a plurality of DC power supplies generated from the DC power produced by the AC-DC converter. According to another aspect, a plurality of phase-offset dimmer control signals are generated based on waveform distortions in a dimming signal produced by a conventional dimmer switch. The phase-offset dimmer control signals are used to individually control the dimming of the light-emitting devices. | 08-28-2014 |
20140247907 | Communications Transmitter Having High-Efficiency Combination Modulator - A communications transmitter includes a combination modulator and a baseband processor configured to generate amplitude, angle, in-phase and quadrature signals. The combination modulator is configured to modulate in the quadrature domain or the polar domain, depending on an output power level of the transmitter and/or the type of modulation scheme being used. When configured to modulate in the quadrature domain, the baseband processor is configured to generate time-varying in-phase and quadrature modulating signals and time-invariant amplitude and angle signals for the combination modulator. When configured to modulate in the polar domain, the baseband processor is configured to generate time-varying amplitude and angle modulating signals and time-invariant in-phase and quadrature signals for the combination modulator. In another embodiment of the invention, the communications transmitter is configurable to operate in three different operational modes: linear, envelope tracking and switch modes. Which operational mode the communications transmitter is configured to transmit depends on the type of modulation scheme being used and/or the transmitter output power level. | 09-04-2014 |