Class / Patent application number | Description | Number of patent applications / Date published |
398193000 | Precompensation (e.g., prechirping, predistortion | 38 |
20080240733 | DISPERSION COMPENSATOR FOR FREQUENCY RESHAPED OPTICAL SIGNALS - An optical transmitter is disclosed including an optical signal source generating a frequency modulated signal encoding data. An optical spectrum reshaper is positioned to receive the frequency modulated signal and converts the frequency modulated signal into a reshaped signal having increased amplitude modulation relative to the frequency modulated signal. A third-order dispersive element is positioned to receive the reshaped signal and is adapted to impose third-order dispersion on the reshaped signal to generate a compensated signal having third-order dispersion effective to compensate for second-order dispersion caused by an optical fiber positioned between the optical transmitter and a receiver. | 10-02-2008 |
20090028578 | Hybrid Optical and Electrical Fiber Optic Link Linearizer - Techniques and systems for reducing nonlinear distortions in an output optical beam from an optical transmitter by using both electrical pre-distortion compensation and optical compensation. | 01-29-2009 |
20090041474 | PREDISTORTION CIRCUIT INCLUDING DISTORTION GENERATOR DIODES WITH ADJUSTABLE DIODE BIAS - A predistortion circuit provides a predistorted input signal that compensates for distortion generated by a non-linear amplifier such as a laser device. The predistortion circuit may be used in an optical transmitter designed for broadband applications, such as a laser transmitter used for forward path CATV applications. The predistortion circuit may include a primary signal path and a secondary signal path that receive an input signal. A second order distortion generator on the secondary signal path generates predistortion of a magnitude corresponding to the magnitude of, but at an opposite phase to, the distortion generated by the non-linear amplifier. The second order distortion generator includes diodes with an adjustable diode bias to control phase, magnitude and/or magnitude/phase versus frequency of the predistortion. | 02-12-2009 |
20090196629 | DISTORTION COMPENSATION CIRCUIT AND METHOD BASED ON ORDERS OF TIME DEPENDENT SERIES OF DISTORTION SIGNAL - A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device. The distortion compensation circuit may be used in an optical transmitter, such as a laser transmitter used for forward path CATV applications. The distortion compensation circuit may include a primary signal path and a secondary signal path that receive an input signal. The secondary signal path produces distortion of a magnitude corresponding to the magnitude of, but at an opposite phase to, the distortion generated by the non-linear amplifier. The secondary signal path includes a plurality of distortion sub-paths with each of the distortion sub-paths configured to produce intermodulation distortion products of the same distortion order but for different frequency dependent orders in a time dependent series representative of the distortion produced by the non-linear amplifier. | 08-06-2009 |
20090196630 | Distortion Compensation Circuit Including One or More Phase Invertible Distortion Paths - A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device and may include a primary signal path for carrying an input signal and one or more secondary signal paths for generating distortion. The distortion compensation circuit may also include one or more controllable phase inverters on at least one of the paths. For example, the secondary signal path may include a distortion generator to produce distortion products from the input signal and a signal controlled phase inverter that inverts the phase of the distortion products. The distortion generator and phase inverter may be combined as an invertible distortion generator. The phase inversion may be controlled in response to a phase inversion control signal generated based on one or more parameters such as temperature. The secondary signal path may also include separate distortion sub-paths to produce frequency independent distortion products and frequency dependent distortion products. | 08-06-2009 |
20090232518 | OPTICAL TRANSMITTER WITH ADAPTIVELY CONTROLLED OPTICALLY LINEARIZED MODULATOR - An optical transmitter for generating a modulated optical signal to be transmitted over fiber optical link. The transmitter includes: an optical source for producing an optical signal; an optically linearized modulator (OLM) as external modulator for modulating the optical signal produced by the optical source with an information carrying signal. The external modulator includes a first input port for receiving a first DC bias signal, and a second input port for receiving a second DC bias signal. The optical transmitter further includes a pilot tone generator for generating a first pilot signal to be applied to the first input port and a second pilot signal to be applied to the second input port. The first and second pilot signals are capable of producing distortion products in the modulated optical signal. A differential modulation signal is imposed onto either the first pilot signal or the second pilot signal so as to generate a first control signal that alternately adjusts the first DC bias signal and the second DC bias signal in order to minimize the distortion products. The optical transmitter may include a digital based control system that is adapted to reduce composite even and odd order distortions in the OLM. | 09-17-2009 |
20100021183 | RF Signal Power Regulation in Optical Transmitters - A circuit controlling the gain of an amplifier in an optical transmitter used for optical communication, including a detection circuit for measuring the power of the RF input to said laser; a gain controller for controlling a gain of said amplifier, and a switch connected to said gain controller, wherein said gain controller is adapted, in response to an activation of said switch, to: (i) automatically vary said gain of said amplifier, and (ii) set said gain of said amplifier at a level corresponding to a reduction in the noise and/or distortion associated with the transmitter. | 01-28-2010 |
20100074630 | SYSTEM AND METHOD FOR SHAPING A WAVEFORM - An optical transmission system for transmitting an optical pulse in a dielectric waveguide, the system including a filter for altering a shape of the optical pulse in both amplitude and phase with respect to time so as to substantially suppress the generation of third-order nonlinearities and increase a power level of the optical pulse, the filter further providing a secure encrypted optical waveform that may be decrypted by a matching optical filter, the system allowing for energy sharing of the pulses to substantially increase system bandwidth. | 03-25-2010 |
20100111542 | Intra-Channel Nonlinearity Compensation For Optical Data Communications - An arrangement is described for compensating intra-channel nonlinearities in an optical communications system which combines optical dispersion compensation with electronic pre-distortion (EPD). EPD with moderate lookup table size can effectively suppress intra-channel nonlinearities over optical transmission links incorporating optical dispersion compensation. The arrangement can be implemented for a variety of optical communications systems, including 10 Gb/s, 40 Gb/s and higher bit rate systems as well as single-channel and wavelength-division multiplexing (WDM) systems. | 05-06-2010 |
20110002698 | HIGH SPEED OPTICAL TRANSMITTER WITH DIRECTLY MODULATED LASER SOURCE - An optical signal transmitter of direct modulation, a method for transmitting optical signals, and an optical network are provided. The optical signal transmitter includes a laser diode operating at a bias current above a lasing threshold of the laser diode; a modulating device applies a modulation signal to the diode to produce a first output optical signal having first and second signal power levels; and a power level discriminator. The power level discriminator, from the received first output optical signal, generates a second output signal of significantly improved extinction ratio by reducing power of one of the first and second signal power levels of the first output optical signal. In one aspect, prior to receipt at the power level discriminator device, the second power level of the first output optical signal ranges from 10% to 60% of the first power level, and the second power level of the second output optical signal is reduced to less than 10% of the first power level of the second output optical signal. | 01-06-2011 |
20110311236 | OPTICAL AMPLIFIER, CONTROL METHOD THEREFOR, AND OPTICAL TRANSMISSION SYSTEM - Provided are an optical amplifier, a control method therefor, and an optical transmission system that can use a simple technique to correct SRS tilt generated in a transmission path after a back-stage amplifier out of two amplifiers, which respectively amplify an input optical signal in a front stage and a back stage of a variable attenuator, in accordance with the number of wavelengths of the optical signal transmitted on the transmission path. A control parameter for controlling the two amplifiers and the attenuator is determined so as to correct a spectral slope caused by stimulated Raman scattering of the optical signal based on network information received from another device, and the two amplifiers and the attenuator are controlled based on the control parameter. | 12-22-2011 |
20120020675 | Method for Energy Efficient Pulsing Operation of Transceivers of a Networked Device - A method performed by a networked device for energy efficient operation of an optical transceiver of the networked device is described herein. It is determined whether a port control of the networked device is enabled to operate in an energy efficient state. Where the port control is enabled to operate in the energy efficient state and an absence of a valid receive energy from a link partner is determined, a laser transmitter of the optical transceiver is pulsed by asserting and de-asserting a control signal. | 01-26-2012 |
20120141142 | DISTORTION COMPENSATION CIRCUIT INCLUDING ONE OR MORE PHASE INVERTIBLE DISTORTION PATHS - A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device and may include a primary signal path for carrying an input signal and one or more secondary signal paths for generating distortion. The distortion compensation circuit may also include one or more controllable phase inverters on at least one of the paths. For example, the secondary signal path may include a distortion generator to produce distortion products from the input signal and a signal controlled phase inverter that inverts the phase of the distortion products. The distortion generator and phase inverter may be combined as an invertible distortion generator. The phase inversion may be controlled in response to a phase inversion control signal generated based on one or more parameters such as temperature. | 06-07-2012 |
20120148261 | METHOD AND SYSTEM FOR OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING WITH COMPANDING TRANSFORM - A companding transform technique is incorporated into orthogonal frequency division multiplexed signals to reduce the peak-to-average ratio of the signals. Prior to the companding transform, an inverse discrete Fourier transform is performed on the signal. Following the companding transform, the signal is compressed, at which point the compressed signal may be advantageously optically transmitted. | 06-14-2012 |
20120148262 | SYSTEM AND METHOD FOR REDUCING MEMORY REQUIREMENTS FOR ELECTRICAL DOMAIN COMPENSATION OF INTRA-CHANNEL NONLINEARITY IN AN OPTICAL COMMUNICATIONS SYSTEM - A digital filter processes an input signal to be conveyed through an optical communications system. The processing generates a predistorted signal using a compensation function that mitigates impairments of the optical communications system. The input signal has a sample period of T, while the predistorted signal has a sample period of T/2. The digital filter has a first branch including a respective first T-spaced filter for processing the input signal using the compensation function to generate a corresponding first output signal comprising nT/2 samples with n odd. A second branch includes a respective second T-spaced filter for processing the input signal with a delay of T relative to the first branch using the compensation function to generate a corresponding second output signal comprising nT/2 samples with n even. A combiner operates to combine the first and second output signals to generate the predistorted signal having a sample period of T/2. | 06-14-2012 |
20120155889 | METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA USING VISIBLE LIGHT COMMUNICATION - A transmitting apparatus using visible light communication generates transmission data into a two-dimensional data code according to a predetermined code method between the transmitting apparatus and a receiving apparatus and transmits the two-dimensional data code through a plurality of light emitting diodes (LED) that are arranged in a two-dimensional form. Therefore, the receiving apparatus senses light from a plurality of LEDs as an image using an image sensor, demodulates the image into a two-dimensional data code, decodes the two-dimensional data code using a code book, and restores data. | 06-21-2012 |
20120163832 | SYSTEM AND METHOD FOR DISTORTION COMPENSATION INCLUDING CONFIGUREABLE DELAY - A distortion compensation circuit including a configurable delay may be used with one or more non-linear elements, such as a laser, to compensate for distortion generated by the non-linear element(s), for example, in broadband RF applications. Embodiments of the distortion compensation circuit may include a primary signal path with a configurable delay segment and a secondary signal path including at least one distortion generator. The configurable delay segment may be selectively configured to provide different delay settings to accommodate different RF loading conditions such that the delayed RF signal on the primary signal path is aligned with the distortion products generated on the secondary signal path when combined to form an RF signal with distortion compensation. | 06-28-2012 |
20120251130 | THERMAL CHIRP COMPENSATION IN A CHIRP MANAGED LASER - Thermal chirp compensation in a chirp managed laser. In one example embodiment, a laser package including a laser and an optical spectrum reshaper configured to convert frequency modulated optical signals from the laser into an amplitude modulated optical signals is provided. A thermal chirp compensation device is in communication with the laser package and a laser driver. The thermal chirp compensation device includes means for generating bias condition and temperature specific thermal chirp compensation signals that each corresponds to a predetermined level of thermal chirp that is induced in the laser by operating the laser at a particular bias condition and temperature. | 10-04-2012 |
20120263481 | NONLINEAR COMPENSATION USING AN ENHANCED BACKPROPAGATION METHOD WITH SUBBANDING - Systems and methods are disclosed to perform nonlinear compensation (NLC) in an optical communication system by applying digital backpropagation (DBP) using a frequency-shaped split-step Fourier method (FS-SSFM), and processing a data block using an overlap-and-save method with a block size M and an overlap factor of N samples between adjacent blocks. | 10-18-2012 |
20130142520 | ANTI-CAUSAL PRE-EMPHASIS FOR HIGH SPEED OPTICAL TRANSMISSION - When a high data rate optical signal travels through a fiber link, its high frequency components tend to experience higher losses due to fiber dispersion (modal and/or chromatic). The loss of high frequency components causes the optical eye to close and the sensitivity to degrade. Disclosed is an apparatus and method for an optical transmitter that relies on anti-causal pre-emphasis to counteract the effect of relaxation oscillation, and therefore brings improvements to optical eye symmetry and mask margin (MM). | 06-06-2013 |
20130216238 | NONLINEAR COMPENSATING APPARATUS AND METHOD AND TRANSMITTER - The present invention provides a nonlinear compensating apparatus and method and a transmitter. The nonlinear compensating apparatus includes: an information sequence acquiring unit, configured to acquire a symbol information sequence of the pulse signal; a perturbation quantity acquiring unit, configured to calculate, by pre-obtained weighting coefficients to which each item corresponds, the weighted sum of interaction items of pulses on one or more moments relative to the current moment; a perturbation quantity processing unit, configured to combine the items of the perturbation quantity based on the weighting coefficients; and an information compensating unit, configured to calculate a difference between the symbol information sequence and the processed perturbation quantity to obtain a compensated symbol information sequence. With the embodiments of the present invention, the complexity of calculation may be further lowered, and requirements on hardware may also be lowered. | 08-22-2013 |
20130287409 | Systems, Circuits and Methods for Filtering Signals to Compensate for Channel Effects - Embodiments of circuits and methods are described for decreasing transmitter waveform dispersion penalty (TWDP) in a transmitter. A data stream is received for transmission across a channel and a main data signal is generated from the data stream. At least two cursor signals are generated where each of the at least two cursor signals are shifted at least a portion of a clock period from the main data signal. The at least two cursor signals are subtracted from the main data signal to generate an output data signal with improved TWDP. Other embodiments include generating a main data signal, a pre-cursor signal shifted on previous clock cycle relative to the main data signal, and a post-cursor signal Shifted one subsequent clock cycle relative to the main data signal. The pre and post cursor signals are subtracted from the main data signal to generate an output data signal. | 10-31-2013 |
20140161469 | HIGH SPEED SIGNAL GENERATOR - A high-speed signal generator. A digital signal processing (DSP) block generates a set of N (where N is an integer and N≧2) parallel digital sub-band signals, each digital sub-band signal having frequency components within a spectral range between 0 Hz and ±Fs/2, where Fs is a sample rate of the digital sub-band signals. A respective Digital-to-Analog Converter (DAC) processes each digital sub-band signal to generate a corresponding analog sub-band signal, each DAC having a sample rate of Fs/2. A combiner combines the analog sub-band signals to generate an output analog signal having frequency components within a spectral range between 0 Hz and ±NFs/2. | 06-12-2014 |
20140219665 | ACTIVE LINEAR AMPLIFIER INSIDE TRANSMITTER MODULE - In one example embodiment, a transmitter module includes a header electrically coupled to a chassis ground. First and second input nodes are configured to receive a differential data signal. A buffer stage has a first node coupled to the first input node and a second node coupled to the second input node. An amplifier stage has a fifth node coupled to a third node of the buffer stage and a sixth node coupled to a signal ground that is not coupled to the chassis ground. An optical transmitter has an eighth node coupled to a seventh node of the amplifier stage and a ninth node configured to be coupled to a voltage source. A bias circuit is configured to couple a fourth node of the buffer stage to a bias current source. | 08-07-2014 |
20140376926 | SYSTEM AND METHOD FOR REMOVING FAR FIELD LIMITATIONS IN MICROWAVE PHOTONIC ARBITRARY WAVEFORM GENERATORS - A photonic waveform generator and a method of generating an electrical waveform based on a photonic signal are disclosed. The generator includes an input port for receiving an optical signal, a pulse shaper coupled to the input port and configured to Fourier transform the optical signal and apply a pre-distort waveform onto optical spectrum of the optical signal, a dispersive pulse stretcher coupled to the pulse shaper, an optical-to-electrical converter coupled to the dispersive pulse stretcher, and an output port coupled to the optical-to-electrical converter, the pre-distortion removes distortion of the electrical signal that exists in the absence of the pre-distortion caused by violation of far field limitation between the optical signal and the electrical signal. | 12-25-2014 |
20140376927 | PLUGGABLE OPTICAL TRANSMITTER MODULE FOR NETWORK OPTICAL TRANSPORT SYSTEM WITH DISTORTION CONTROL - Linearized optical transmitter units are described for a hybrid optical fiber coaxial cable network. The linearized optical transmitter unit can comprise a directly-modulated or externally-modulated laser optically coupled to an optical conduit directed to an optical fiber communications link and electrically coupled to an electrical RF source line that provides an RF source to drive the laser or an external modulator for a light beam from the laser. A linearization information electrical component comprising memory and/or a processor, and a data output configured to transmit linearization enabling data for input into a direct digital synthesis engine that enables the direct digital synthesis engine to generate an RF signal wherein nonlinear responses of the transmitter and/or the optical fiber communications link are pre-compensated, in which the data is specific for the optical transmitter and/or the optical fiber communications link. An electronic communication channel can connected to the data output of the electrical component to communicate the linearization enabling data external to the linearized optical transmitter unit suitable for communication to the direct digital synthesis engine. The linearized optical transmitter can be assembled in a plug-in module. Corresponding HFC systems and methods are also described. | 12-25-2014 |
20150078762 | SIGNAL GENERATING CIRCUIT, OPTICAL SIGNAL TRANSMITTING APPARATUS, SIGNAL RECEIVING CIRCUIT, METHOD FOR ESTABLISHING OPTICAL SIGNAL SYNCHRONIZATION, AND OPTICAL SIGNAL SYNCHRONIZATION SYSTEM - To enable signal position detection, frequency offset compensation, clock offset compensation, and chromatic dispersion amount estimation in a communication system based on coherent detection using an optical signal, even on a signal having a great offset in an arrival time depending on a frequency due to chromatic dispersion. An optical signal transmitting apparatus generates specific frequency band signals having power concentrated on two or more specific frequencies and transmits a signal including the specific frequency band signals. An optical signal receiving apparatus converts a received signal into a digital signal, detects positions of the specific frequency band signals from the converted digital signal, estimates frequency positions of the detected specific frequency band signals, and detects a frequency offset between an optical signal receiving apparatus and an optical signal transmitting apparatus. Moreover, the optical signal receiving apparatus detects a clock offset between the optical signal receiving apparatus and the optical signal transmitting apparatus from an interval between the estimated frequency positions of the specific frequency band signals. Furthermore, the optical signal receiving apparatus estimates temporal positions of the detected specific frequency band signals and detects a chromatic dispersion amount from a difference between the temporal positions of the specific frequency band signals corresponding to different frequencies. | 03-19-2015 |
20150086218 | DISPERSION MANAGEMENT FOR INHOMOGENEOUS FIBER-OPTIC LINKS - Methods and apparatus for managing the effects of dispersion in an optical transport system in which some of the system's nodes are connected to one another via inhomogeneous fiber-optic links. In one embodiment, an optical transmitter is configured to apply electronic and/or optical dispersion pre-compensation in the amount selected to cause the peak-to-average-power ratio of the optical signal in the lower-dispersion portion of the link to be relatively low (e.g., close to a minimum value). Advantageously, such dispersion pre-compensation tends to significantly reduce, e.g., in terms of the bit-error rate, the directional anisotropy exhibited by optical transmissions through the inhomogeneous fiber-optic links. | 03-26-2015 |
20150104196 | ELECTRONIC DISPERSION COMPENSATION FOR LOW-COST DISTRIBUTED FEEDBACK-DIRECTLY MODULATED LASER - Exemplary embodiments of the present invention relate to electronic dispersion compensation (EDC). The interaction between the frequency chirp and the fiber dispersion is newly analyzed. The linear and nonlinear properties of the chirp-dispersion are separately analyzed. A pre-compensating transmitter may consist of a phase interpolator (PI), a 2 tap data generator, a pulse widening CLK generator, a rising pattern detector, 4:1 Mux and an output driver. A post-compensating receiver may consist of linear equalizer for the rabbit ear compensation, nonlinear equalizer for tilting compensation, typical high frequency boosting equalizer (EQ) and limiting amp (LA). | 04-16-2015 |
20150372766 | OPTICAL TRANSMISSION SYSTEM, PHASE COMPENSATION METHOD, AND OPTICAL RECEPTION APPARATUS - An increase in circuit scale is suppressed and a phase variation caused in a transmission path or the like is compensated for. An optical transmission system includes: a pilot symbol detection unit which detects a plurality of pilot symbols intermittently inserted into a received complex electric field signal that is obtained through coherent detection for a received optical signal; an error signal computation unit which calculates a complex electric field error signal indicating a phase variation at each pilot symbol based on the pilot symbols detected by the pilot symbol detection unit and a predetermined reference symbol; a compensation electric field signal generation unit which estimates a phase variation between the pilot symbols in the received complex electric field signal using filter processing based on the complex electric field error signal calculated by the error signal computation unit; and a phase noise compensation unit which performs phase compensation for the received complex electric field signal based on the phase variation between the pilot symbols estimated by the compensation electric field signal generation unit. | 12-24-2015 |
20160006515 | Method for Generating Constant Modulus Multi-Dimensional Modulations for Coherent Optical Communications - A method generates constant modulus multi-dimensional modulations for coherent optical communications by first projecting points in a constellation of the code onto a Poincare sphere or its higher-dimensional hyper-sphere. By using meta-heuristic procedures, nonlinear programming and gradient search methods, constellation points in the hyper-sphere are optimized in certain criteria, such as maximizing the minimum Euclidean distance, minimizing the union bound, minimizing the bit-error rate, minimizing the required signal-to-noise ratio, maximizing the nonlinear fiber reach, maximizing the phase noise tolerance, and maximizing the mutual information. Some methods use parametric unitary space-time block codes such as Grassmannian packing, and filter impulse response as well as unitary rotation over adjacent code blocks to generate near-constant modulus waveform, not only at the symbol timing, but also over the entire time. | 01-07-2016 |
20160028490 | DIRECTLY MODULATED LASER WITH DISPERSION COMPENSATION - Systems and methods for using a dispersion compensation circuit to directly modulate a laser. | 01-28-2016 |
20160036470 | METHOD AND APPARATUS FOR SIGNAL EDGE BOOSTING - Described is an apparatus for boosting a transition edge of a signal, the apparatus comprises: a logic to provide input data having a Unit Interval (UI); a programmable delay unit to receive the input data and operable to delay the input data by a fraction of the UI to generate a delayed input data; and one or more drivers to drive the input data and the delayed input data to a node. | 02-04-2016 |
20160065311 | FEEDBACK FOR ELECTRONIC PRE-DISTORTION IN AN OPTICAL TRANSMITTER - We disclose an optical transponder, in which one or more all-electronic feedback paths are used to obtain a relatively accurate estimate of the device-specific signal distortions in the transmitter portion thereof. The obtained estimate is used to enable the digital signal processor of the optical transponder to carry out electronic pre-distortion (EPD) that can significantly reduce or cancel these signal distortions without the use of detailed factory-calibration measurements or optics dedicated to feedback purposes. The use of all-electronic feedback paths may enable a beneficial reduction in the cost of the EPD functionality, e.g., by eliminating a significant extra cost associated with the implementation of optically generated feedback. | 03-03-2016 |
20160087676 | OPTICAL TRANSMITTER - An optical transmitter includes four LDs, four LDDs that drive the LDs, four monitoring PDs that convert some of optical signals emitted from the LDs to electrical sisals and output them, a controller that controls the LDDs in response to the electrical monitoring signals generated by the monitoring PDs, and a switch that receives the electrical monitoring signals though signal lines from the monitoring PDs and electrically connects only a selected signal line selected by the controller to the controller. The controller outputs a selection signal that selects the selected signal line from the signal lines is order to the switch, and controls the LDDs so that an optical power of the LD corresponding to the PD approaches a predetermined value, according to the electrical monitoring signal outputted from the PD corresponding to the selected signal line. | 03-24-2016 |
20160094295 | NEAR-THRESHOLD OPTICAL TRANSMITTER PRE-DISTORTION - Methods an systems for low-power transmission include biasing an emitter in a non-linear operating range of the emitter near a threshold current of the emitter. A data signal is distorted to add a precursor pulse to a rising edge of a data waveform to quickly bring the emitter into a linear operating range. The distorted data signal is transmitted at the emitter. | 03-31-2016 |
20160380700 | METHOD FOR ELIMINATING NONLINEAR EFFECTS, TRANSMITTER AND RECEIVER - The present disclosure discloses a method for eliminating nonlinear effects, a transmitter and a receiver. The method includes: setting signals to be transmitted and redundant signals, where the redundant signals are symmetrical to the signals, which are to be transmitted, about Y axis; and after the setting is completed, respectively executing dispersion pre-compensation on the signals to be transmitted and the redundant signals, and executing signal modulation after the dispersion pre-compensation is completed. | 12-29-2016 |
20180024175 | METHOD AND APPARATUS TO EVALUATE AUDIO EQUIPMENT FOR DYNAMIC DISTORTIONS AND OR DIFFERENTIAL PHASE AND OR FREQUENCY MODULATION EFFECTS | 01-25-2018 |