Abstract: 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.

Abstract: 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.

Abstract: Disclosed herein are methods and apparatus for processing an input information signal having varying amplitude and phase to obtain an amplified output signal having the same amplitude and phase variation. In an exemplary method, an input information signal is decomposed into two pairs of constant-envelope component signals such that the vector sum of the first pair is orthogonal to the vector sum of the second pair, for desired signal amplitudes below a level corresponding to a pre-determined threshold. For desired signal amplitudes above this level, the input information signal is instead decomposed into two pairs of constant-envelope component signals such that the vector sum of the first pair is separated by less than ninety degrees from the vector sum of the second pair. The constant-envelope component signals may be amplified by highly-efficient non-linear amplifier elements and combined to obtain the amplified output signal.

Abstract: The present invention addresses the problem to extend the dynamic power range where the amplifier operates linearly for a full input amplitude swing with improved efficiency. According to the present invention, the above presented problem is solved by changing the delivered power to the load by changing the value of the load and still keeping the amplifier in its linear condition. The invention enables the amplifier to maintain high efficiency over a wider power range.

Abstract: Systems and methods related to amplifier systems which use a predistortion subsystem to compensate for expected distortions in the system output signal. A signal processing subsystem receives an input signal and decomposes the input signal into multiple components. Each signal component is received by a predistortion subsystem which applies a predistortion modification to the component. The predistortion modification may be a phase modification, a magnitude modification, or a combination of both and is applied by adjusting the phase of the fragment. The predistorted component is then separately processed by the signal processing subsystem. The processing may take the form of phase modulation and amplification. The phase modulated and amplified components are then recombined to arrive at an amplitude and phase modulated and amplified output signal. The predistortion modification is applied to the components to compensate for distortions introduced in the signal by the signal processing subsystem.

Abstract: Linearization circuits of the invention are used in conjunction with power amplification circuits that comprise a power amplifier core. Exemplary linearization circuits comprise a replica of the power amplifier core. In operation, the linearization produces an envelope signal from an RF signal. The envelope signal is used to control the replica to produce an analog output signal which represents the inverse of the AM to AM distortion of the power amplifier core. The linearization circuit then biases the RF signal with the inverted non-linear signal of the replica to control the power amplifier core. The power amplifier core and the replica thereof can be defined on the same semiconductor die so both respond to process variables similarly.

Abstract: 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.

Abstract: 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.

Abstract: A system for processing an input signal, the system including: (a) a hardware memory module configured to store a lookup table; and (b) 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 t

Abstract: 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.

Abstract: The invention aims to converge predistortion coefficients efficiently in a predistorter adapted to compensate for distortion generated in an amplifier. Level detection means detects the level of a signal input to an amplifier. Signal acquisition means acquire a signal output from the amplifier as a feedback signal. Correspondence acquisition means updates a predistortion coefficient expressed using a set of orthogonal polynomials so that a distortion component contained in the acquired feedback signal is reduced and acquires a correspondence between the level of the signal input to the amplifier and a control coefficient for predistortion (contents of a distortion compensation table). Predistortion executing means applies distortion for predistortion with respect to the signal input to the amplifier in accordance with the control coefficient for predistortion that corresponds to the detected level based on the acquired correspondence.

Abstract: An RF signal, which has been obtained by a quadrature modulation, is corrected without performing quadrature demodulation. There are included an in-phase multiplier, a quadrature multiplier, an adder, a power detector, and an error determining part. The in-phase multiplier outputs an in-phase conversion signal by mixing an in-phase local signal of a predetermined local frequency with an in-phase correction user signal obtained by adding an in-phase user signal to an in-phase correction signal of a sinusoidal voltage outputted from an in-phase correction signal output unit. The quadrature multiplier outputs a quadrature conversion signal by mixing a quadrature local signal, which is different in phase by 90 degrees from the in-phase local signal, with a quadrature correction user signal obtained by adding a quadrature user signal to a quadrature correction signal, which is different in phase by 90 degrees from the in-phase correction signal, from a quadrature correction signal output unit.

Abstract: An apparatus for amplifying a signal. The apparatus includes an amplifier powered by a power supply, a monitor that monitors an output signal of the amplifier and a controller operative to adjust the power supply if distortion is detected in the output signal of the amplifier by the monitor.

Abstract: 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.

Abstract: 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.

Abstract: The present invention is an RF cancellation circuit located between the output of a power amplifier and downstream circuitry, such as a transmitting antenna. The RF cancellation circuit cancels reflections resulting from antenna impedance mismatches, thereby presenting a constant load impedance to the output of the power amplifier. The RF cancellation circuit extracts a portion of the reflected signal, phase-shifts by 180 degrees and amplifies the extracted portion of the reflected signal to create a cancellation signal, and then cancels the balance of the reflected signal by adding in the cancellation signal. Directional circuitry is used to process the reflected signals without interfering with normal transmitted signals. Presenting a constant load impedance to the output of the power amplifier helps facilitate compliance with total radiated power into load mismatch specifications.

Abstract: 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.

Abstract: The power amplifier mainly includes a main amplifier, two splitters, one combiner, one subtracter, two phase shifters, one attenuator and one error amplifier. The splitters, subtracter and combiner are designed in the form of 90-degree or quadrature hybrid couplers. A quadrature hybrid can be implemented with any lumped or transmission-line elements and has an important advantage compared to the in-phase splitter that at equal values of reflection coefficients from loads connected to the in phase and 90° phase shift terminals, the reflection wave is lacking at the main input terminal and, consequently, the input voltage standing wave ratio of a quadrature hybrid does not depend on the equal load mismatch level.

Abstract: 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.

Abstract: Low noise amplifier circuit. The low noise amplifier circuit includes an amplifier that amplifies an input to provide an output. The amplifier is coupled to an input terminal. The circuit also includes a device in a cascode connection with the amplifier. The circuit further includes a tuning circuit coupled to the device to phase shift the output. Further, the circuit includes a feedback circuit that is responsive to a phase-shifted output to enhance gain of the amplifier. The feedback circuit is coupled to the tuning circuit and the amplifier.

Abstract: Techniques for improving the linearity of a cascode amplifier. In an exemplary embodiment, an auxiliary common-gate amplifier is provided in parallel with the principal cascode branch. The auxiliary common-gate amplifier samples a cascoded node in the principal cascode branch. The auxiliary common-gate amplifier generates a current which, when combined with the current generated by the principal cascode branch, cancels a distortion component to generate an output current with improved linearity characteristics. In an exemplary embodiment, a phase shifting network couples the cascoded node to the auxiliary common-gate amplifier, and may include, e.g., a capacitor coupled to an inductor.

Abstract: An apparatus and method for the cancellation of third order derivative distortion for ultra low power (ULP) applications are disclosed involving a first amplifier connected in parallel with a second amplifier for amplifying a received signal. The first amplifier includes at least one transistor operating in the sub-threshold region such that the first amplifier possesses a positive third derivative of a transfer function of the first amplifier, which generates a first amplified signal having in phase third order distortions. The second amplifier includes at least one differential pair of transistors operating in the sub-threshold region such that the second amplifier possesses a negative third derivative of a transfer function of the second amplifier, which generates a second amplified signal having in opposite phase third order distortions. The first and second amplified output signals are combined resulting in cancellation of third order distortions in the combined amplified signal.

Abstract: 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.

Abstract: 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 8z), a power amplifier (PA) and a linearizer module (LM).

Abstract: A device may include an envelope detector to generate an envelope signal from the input signal, a drain bias controller to adjust a drain bias of the amplifier based on the envelope signal, a gate bias controller to adjust a gate bias of the amplifier based on the envelope signal, a predistortion controller to predistort the input signal based on the envelope signal, based on the adjusted drain bias, and based on the adjusted gate bias, and to output the predistorted signal, and an amplifier to receive the predistorted signal and to generate an amplified output signal from the predistorted signal. The device may be selectable to operate in a linear mode or a nonlinear mode. The nonlinear mode may be selected by applying a large gate offset bias.

Abstract: 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.

Abstract: Systems and methods for achieving linear amplification with high efficiency are provided. An input signal is amplified using a plurality of amplifiers by dividing the input signal into a plurality of inputs signals, amplifying the plurality of input signals with the plurality of amplifiers and combining the amplified output signals of the plurality of amplifiers into a single amplified output signal. Coefficients are applied to the input signals and the amplified output signals of the amplifiers so that non-linear products due to the amplifiers are suppressed when the amplified output signals of the amplifiers are combined into the single amplified output signal. The suppression of the non-linear products allows an amplification system to achieve linear amplification using high efficiency non-linear amplifiers. The systems and methods can also be applied to other non-linear devices, for example, mixers and modulators, to suppress non-linear products in these devices.

Abstract: Apparatus is presented for broadcasting an RF signal. This includes a signal divider that receives a composite RF signal and provides therefrom first and second signals each having digital and analog components. A phase extractor receives the first signal and provides therefrom a phase modulated RF signal for application to an amplifier. A gain controller varies the gain of the amplifier in accordance with amplitude variations of the second signal.

Abstract: 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.

Abstract: A method, circuit and system for determining at least one of an amplitude and a relative phase of a signal under test. A reference signal is generated based, at least in part, upon the at least one of the amplitude and the relative phase of the signal under test. The reference signal is combined with the signal under test to generate a residual signal indicative of a distortion within the signal under test. The residual signal is measured.

Abstract: 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.

Abstract: Methods and apparatus for amplifier AM and PM predistortion and autocalibration. AM and PM amplifier distortion can be corrected using predistortion. The AM and PM distortion characteristics of the amplifier are determined using an autocalibration technique. The amplifier characteristics can be stored in distinct look up tables. Alternatively, the inverse of the amplifier characteristics can be stored in distinct look up tables. Signals that are to be amplified are characterized in polar format having a phase component with a normalized magnitude and a magnitude component. The phase component can be predistorted by applying the inverse of the PM distortion characteristics to the signal. Similarly, the magnitude component can be predistorted by applying the inverse of the AM distortion characteristics to the signal. The predistorted phase component can be amplified using the previously characterized amplifier.

Abstract: In one embodiment, an amplifier circuit is formed to minimize pop and click noise on the outputs of the amplifier circuit. The amplifier circuit is configured to place an output stage of the amplifier circuit in a high impedance state to minimize the pop and click noise. In another embodiment, the amplifier circuit is configured to couple the inputs of two amplifiers together to minimize the pop and click noise.

Abstract: A wireless communications system includes a first multiplexer distribution network fed by a radio frequency input; a plurality of multi-stage power amplifiers fed by the first multiplexer distribution network, wherein each one of the multi-stage power amplifiers includes: a pre-distortion linearizer fed from the first distribution network; a first combiner receiving input from the pre-distortion linearizer; a second combiner; a plurality of power amplifier cells fed by the first combiner and feeding the second combiner; and a second multiplexer distribution network, wherein the second multiplexer distribution network is fed by the second combiner and feeds a radio frequency output.

Abstract: 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.

Abstract: A modulation circuit according to the present invention includes: a modulator modulating a received signal and outputting a modulated signal; a detector circuit receiving the modulated signal and outputting a envelope of the modulated signal; and a first controller regulating an offset level of the modulator based on the envelope.

Abstract: 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.

Abstract: In a distortion generation path of a power series predistorter, a frequency characteristic compensator that adjusts the frequency characteristic of a distortion component is provided in series with an odd-order distortion generator. The output of a power amplifier is divided to obtain an output signal of the power amplifier, the output signal of the power amplifier is down-converted by a down converter, and a distortion detector detects a distortion component in the down-converted signal of base band. The frequency characteristic of the distortion component is split into windows each having a band width of ?f by a distortion component frequency characteristic splitter, and the power of the distortion component in each window is detected. Based on the detected power, the frequency characteristic compensator adjusts a part of the frequency characteristic of the distortion component associated with each window.

Abstract: Recently, the use of class-D audio amplifiers has become more and more widespread. In contrast to the generally employed class-AB linear amplification technology, class-D allows for improved efficiency. However, the class-D principle is known for its poor distortion characteristics. According to the present invention a digital amplifier (18) is provided for converting an audio signal to a power output, comprising a ripple suppression circuit (16) for suppressing voltage ripples in a supply voltage supplied to the bridge circuit with (6) at least one pair of switches. The ripple suppression circuit (16) suppresses ripples in the supply voltage supplied to a switch in the bridge circuit (6), which has been found to cause a major part of the distortions in the output signal of the digital amplifier (18).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An RF transmitter (10) includes an RF amplifier (22) that experiences gain-droop distortion as a result of self-heating. A heat compensator (20) is included to insert a gain boost of an amount which is the inverse of the gain droop experienced by the RF amplifier (22). The amount of gain boost is determined by generating a heat signal (88) from low-pass filtering (86) the squared magnitude (82) of a communication signal (14). The heat signal (88) is scaled by a weighting signal (68) estimated by monitoring the amplified RF signal (42) at the output of the RF amplifier (22). A nonlinear relationship section (96) then transforms the scaled signal into a gain-boost signal (94) that corresponds to the inverse of gain droop in the RF amplifier (22).

Abstract: Amplifiers with improved linearity and noise performance are described. In an exemplary design, an apparatus includes first through sixth transistors. The first transistor receives an input signal and provides an amplified signal. The second transistor receives the amplified signal and provides signal drive for an output signal. The third transistor receives the input signal and provides an intermediate signal. The fourth transistor provides bias for the third transistor in a high linearity mode. The fifth transistor receives the intermediate signal and provides signal drive for the output signal in a low linearity mode. The third and fourth transistors form a deboost path that is enabled in the high linearity mode to improve linearity. The third and fifth transistors form a cascode path that is enabled in the low linearity mode to improve gain and noise performance. The sixth transistor generates distortion component used to cancel distortion component from the first transistor.

Abstract: Systems, methods, and apparatuses are provided for linear envelope elimination and restoration transmitters that are based on the polar modulation operating in conjunction with the orthogonal recursive predistortion technique. The polar modulation technique enhances the battery life by dynamically adjusting the bias level. Further, the analog orthogonal recursive predistortion efficiently corrects amplitude and phase errors in radio frequency (RF) power amplifiers (PA) and enhances the PA output capability. Additionally, even-order distortion components are used to predistort the input signal in a multiplicative manner so that the effective correction bandwidth is greatly enhanced. Also, the predistortion scheme, which uses instantaneously feed-backed envelope distortion signals, allows for correction of any distortion that may occur within the correction loop bandwidth, including envelope memory effects.

Abstract: 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.

Abstract: 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.

Abstract: One embodiment of the present invention is a method for producing a system for describing an electrical network. An output signal of the electrical network is sampled at a frequency that corresponds to the Nyquist criterion for the input signal to the electrical network. A model with a memory is developed for the output signal, which is sampled at a low sampling rate, with this model approximating the output signal. The model is then transformed by suitable interpolation to an interpolated model with a memory. The interpolation results in the model created in this way providing a good approximation to an output signal which is sampled at a high frequency. The resultant system can be used for predistortion.

Abstract: 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.

Abstract: 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.