Abstract: A radio frequency equalizer includes a first resistor coupled to an input terminal, a second resistor coupled between the first resistor and an output terminal, a first capacitor, a first inductor, a first switch coupled to the input terminal, the first capacitor and the first inductor, a second switch coupled to the output terminal, the first capacitor and the first inductor, a second capacitor, a second inductor and a third switch coupled to the first resistor, the second resistor, the second capacitor and the second inductor. According to a control signal, the first switch selectively couples the first capacitor or the first inductor to the input terminal, the second switch selectively couples the first capacitor or the first inductor to the output terminal and the third switch selectively couples the second capacitor or the second inductor to the first resistor and the second resistor.

Abstract: An RF linearizer and an associated method are provided for linearizing a power amplifier. The RF linearizer may include: (a) a quadrature up-converter for up-converting a baseband input signal that is to be transmitted by the power amplifier; (b) an RF analog predistorter controlled by a set of coefficients for predistorting the up-converted input signal; (c) a down-converter for down-converting an output signal of the power amplifier; (d) an error monitor receiving the down-converted output signal and the input signal for providing an error signal; and (e) a signal analyzer receiving the error signal, the signal analyzer using an out-of-band power spectrum of the error signal to optimize the set of coefficients. The input signal may have an in-phase component and a quadrature component.

Abstract: According to the present disclosure, a method for tracking power levels of a wireless communications signal comprises receiving a feedback signal indicative of a power level of a wireless communication signal associated transmitted from a transmit path to an antenna of a wireless communication element. The method further comprises receiving a reference signal associated with a digital signal converted into the wireless communication signal. Additionally, the method comprises determining a gain of the feedback signal with respect to the reference signal and determining a gain error based on the determined gain and an expected gain.

Abstract: The present disclosure generally relates to predistortion that compensates for non-linearity of a power amplifier as well as short-term and long-term memory effects of the power amplifier. In one embodiment, a transmitter includes a power amplifier that amplifies a power amplifier input signal to provide a power amplifier output signal, a predistortion sub-system that effects predistortion of the power amplifier input signal to compensate for non-linearity of the power amplifier and memory effects of the power amplifier, and a adaptation sub-system that adaptively configures the predistortion sub-system. The predistortion sub-system includes a memory-less predistortion component that compensates for the non-linearity of the power amplifier, a Finite Impulse Response (FIR) filter that compensates for short-term memory effects of the power amplifier, and an Infinite Impulse Response (IIR) filter that compensates for long-term memory effects of the power amplifier.

Abstract: An RF circuit having a transcoupler, a multifunctional RF-circuit element that can operate both as an impedance inverter and as a signal coupler. When connected to a fixed load impedance, the transcoupler can also operate as an impedance transformer. The impedance-transformer/inverter functionality of the transcoupler can be used, e.g., to modulate the load of a power amplifier. The signal coupler functionality of the transcoupler can be used, e.g., to generate a corresponding feedback signal indicative of phase and/or amplitude distortions in the amplifier. The use of various embodiments of the transcoupler in an RF circuit can be advantageous, for example, because the transcoupler has a lower insertion loss than a cascade consisting of a prior-art impedance inverter and a prior-art directional coupler, occupies a relatively small area on the printed circuit board, and helps to reduce the per-unit fabrication and operating costs.

Abstract: Embodiments of the present invention provide a system and method for power amplifier control. Before a fixed gain amplifier is disabled and after an automatic gain controller adjusts gain for the last time, a reference transmit power value is read from the automatic gain controller. A gain level is read from the fixed gain amplifier. The reference transmit power value and the gain level are saved in a storage module. Before the fixed gain amplifier is enabled and after the automatic gain controller adjusts gain for the last time, the reference transmit power value saved in the storage module is written into the automatic gain controller and the gain level saved in the storage module is written into the fixed gain amplifier.

Abstract: A circuit for linearizing a power amplifier. The circuit includes a main signal path comprising a digital-to-analog converter, wherein a main signal is transmitted through the main signal path to said power amplifier; and a digital pre-distortion path disposed outside of the main signal path, wherein the digital pre-distortion path includes a digital pre-distorter for digitally pre-distorting the main signal.

Abstract: A processor determines, from signals received from other communication devices, one selected transmission mode for the communication channel conditions. The processor projects multiple channel characterization parameters in a mathematical model to each of the candidate transmission modes using a model of nominal communication channel conditions to predict whether each of the candidate transmission modes will achieve the desired communication under the nominal communication channel conditions. This results in the generation of a first subset of transmission modes. The processor also projects the multiple channel characterization parameters to each of the candidate transmission modes using a model of degraded communication channel conditions to predict whether each of the candidate transmission modes will achieve the desired communication under the degraded communication channel conditions.

Abstract: A transmission module including a power supply voltage control unit that sets a power supply voltage to the high frequency amplifier in a variable manner, and a control circuit that controls an amplitude control unit, a phase control unit and the power supply voltage control unit. The control circuit and the power supply voltage control unit control the power supply voltage in accordance with an output power of the high frequency amplifier. The transmission module can carry out not only phase control but also amplitude control in a continuous manner, while suppressing amplitude and phase variation, and a high frequency amplifier in the transmission module is made highly efficient. In addition, a large directional gain, a low side lobe level and a low power consumption are achieved, as a phased array antenna apparatus using a transmission module.

Abstract: There is provided a communication apparatus including a voltage detection unit for detecting an antenna end voltage of a reader or a non-contact type IC card when non-contact communicating using a load modulation of the non-contact type IC card with respect to a magnetic field signal from the reader/writer; and a characteristics control unit for changing characteristics of the antenna of the reader/writer or the non-contact type IC card when the antenna end voltage detected by the voltage detection unit reaches a predetermined first threshold value.

Abstract: A method of medical diagnosis and monitoring using equipment that has wireless electrodes, which are attached to the surface of the skin of the patient. The method comprises collection of data from a patient, converting the data to digital form and transmitting the digital data wirelessly from a patient to a base station located away from the patient where in the wireless transmission between the patient and base station is bi directional.

Abstract: A transmitter includes an input, a modulator, and a calibration memory configured to store discrete calibration test points. A compensator is coupled between the input and the modulator and cooperates with the calibration memory to cause the modulator to generate a respective calibration carrier signal for each of the discrete calibration test points during a calibration phase. A detector is coupled to an output of the modulator and is configured to determine respective calibration values of the calibration carrier signals during the calibration phase. A compensator calculator is coupled to an output of the detector, and is configured to generate compensation values for the compensator for use during an operation phase and based on the calibration values of the calibration carrier signals.

Abstract: A PAPR determining device includes a detecting unit and a PAPR determining unit. The detecting unit detects a predetermined value's changes, which is a cause of changes in a saturation power of a power amplifier. When the detecting unit detects any change in the predetermined value, the PAPR determining unit determines a PAPR value that corresponds to the saturation power of the power amplifier.

Abstract: Systems and methods for measuring transmitter and/or receiver I/Q impairments are disclosed, including iterative methods for measuring transmitter I/Q impairments using shared local oscillators, iterative methods for measuring transmitter I/Q impairments using intentionally-offset local oscillators, and methods for measuring receiver I/Q impairments. Also disclosed are methods for computing I/Q impairments from a sampled complex signal, methods for computing DC properties of a signal path between the transmitter and receiver, and methods for transforming I/Q impairments through a linear system.

Abstract: Apparatus for generating a plurality of radio-frequency RF subcarrier signals for transmission between two adjacent ultra-high frequency UHF broadcast channels comprises a signal generator for generating a plurality of local oscillator LO signals, and a plurality of mixers each arranged to mix one of the LO signals with one of a plurality of input signals to generate one of the RF subcarrier signals, said input signal including information to be transmitted by said RF subcarrier signal. Variable gain amplifiers can be provided to independently amplify the RF subcarrier signals before they are combined. The LO signals can have the same frequency and the input signals can have different frequencies, or the LO signals can have different frequencies and the input signals can have the same frequency. A second LO signal with a different frequency to a first LO signal can be obtained by dividing a reference frequency by a predetermined value and mixing with the first LO signal.

Abstract: Aspects of a method and system for best-M CQI feedback together with PMI feedback may include generating a plurality of feedback messages, which may be communicated from a mobile station to a base station, wherein at least one of the generated plurality of feedback messages may be associated with each corresponding selected one of a plurality of Channel Quality Indicator (CQI) reporting units. The at least one of the generated feedback messages may comprise CQI information and Pre-coding Matrix Index (PMI) information, which may both be associated with the selected one of the plurality of CQI reporting units. At least one other of the generated plurality of feedback messages may comprise an aggregate CQI information, which is based on one or more of the plurality of CQI reporting units.

Abstract: A method and system for wireless communication is provided and may include mitigating blocker signals in transmitted RF signals in a wireless device including a transmitter front end. The mitigation may include up-converting a baseband signal, mixing the up-converted baseband signal with a feedback signal, and amplifying the mixed up-converted baseband signal and the feedback signal to generate an output signal. The feedback signal may be generated by down-converting the output signal, low-pass filtering the down-converted output signal, and up-converting the filtered down-converted signal for the summing. The blocker signals may correspond to receive frequencies for the wireless device and may be converted to DC via the down-converting. The wireless devices may operate in accordance with at least a CDMA standard.

Abstract: A mobile wireless communications device may include a portable device housing, wireless communications circuitry carried by the portable device housing, and a self-contained rechargeable battery pack carried by the portable housing for powering the wireless communications circuitry. The self-contained rechargeable battery pack may include a battery casing, at least one internal battery cell carried within the battery casing, internal battery circuitry carried within the battery casing, and at least one internal filter element carried within the battery casing and coupled to the internal battery circuitry.

Abstract: A technique of suppressing noise in a transmitter device (300) is provided, wherein the transmitter device (300) comprises a baseband signal processing stage (301) operating at baseband frequency and comprising a modulator (316, 320) for converting a baseband signal into an RF signal, and an RF signal processing stage (301) operating at RF and comprising an amplifier (330).

Abstract: A transmitter/receiver for a wireless communication system is provided. The transmitter for a wireless communication system includes: an external amplifier connected to a next stage of a power amplifier amplifying a signal to be transmitted to a required power level; a transmission selector configured to directly output the signal amplified by the power amplifier to an antenna or control the external amplifier to amplify the signal, based on a mode control signal; and a mode selector configured to compare a power level of a signal provided from a receiver with a predetermined power level to generate the mode control signal for determining whether or not to operate the external amplifier.

Abstract: A power amplifier power controller in the power amplifier system monitors various operating conditions of the power amplifier, and controls the output transmit power of the power amplifier by coordinated control of both the input drive level to the power amplifier and the gain of the power amplifier. The power amplifier power controller controls the input drive level to the power amplifier so that the input drive level does not change substantially while adjusting the gain of the power amplifier to maximize the transmit power. The power amplifier power controller may also adjust the input drive level by some portion of the overall change required to the power of the power amplifier, while adjusting the gain of the power amplifier by the remaining portion of such overall change.

Abstract: An embodiment of the invention is a system for signal processing in preparation for wireless transmission, the wireless transmission being from a portable wireless communication device and including use of a power amplifier having nonlinear characteristics. The system includes memory for storing digitally-indexed information. The digitally-indexed information models nonlinear characteristics of the power amplifier, and the digitally-indexed information is stored prior to processing of a first signal that reflects information to be communicated. The system further includes first logic, configured to accept the first signal and to retrieve, based on the first signal, a portion of the digitally-indexed information stored in the memory, and second logic, configured to generate a second signal based on the portion of the digitally-accessed information and on the first signal.

Abstract: Some demonstrative embodiments include devices, systems and/or methods of detecting transmitter power. For example, a device may include a power detection circuit, coupled by a first coupler to a transmit chain, to provide a first output representing a measured non-calibrated transmission power over the transmit chain; a reference circuit, coupled to a reference voltage by a second coupler, to provide a second output representing a measured reference coupling factor; and a calibrator to determine a calibrated transmission power over the transmit chain based on the first and second outputs.

Abstract: Embodiments for at methods, apparatus and systems for operating a voltage regulator are disclosed. One method includes generating, by a switching controller, a switching voltage through controlled closing and opening of a series switch element and a shunt switch element. Further, the method includes generating, by a switchable output filter, a regulated output voltage by filtering the switching voltage, wherein the switchable output filter comprises a plurality of capacitors that are selectively included within the switchable output filter.

Abstract: Apparatus and method for reducing the current consumption and increasing the efficiency of an RF power amplifier (PA), according to which the load, connected to the output stage of the PA, tuned dynamically or statically for each level of the desired output power. By doing so, the output impedance of the output stage is essentially matched, such that the dynamic RF load line has a slope that corresponds to the impedance required to provide this level. Whenever a smaller output power is desired in response to reduction in the input signal to the amplifier, the load is further tuned, such that the dynamic or static RF load line has a slope that causes the power amplifier to essentially remain in saturation at the smaller output power.

Abstract: An envelope tracking power amplifier system time-aligns a supply voltage to an input signal to a power amplifier. The power supply operates in a static mode for low amplitude input signals and operates in a dynamic mode for high amplitude input signals. In the static mode, the power supply produces a substantially constant supply voltage independent of the amplitude of the input signal. In the dynamic mode the power supply produces a dynamically varying envelope tracking supply voltage based on the amplitude of the input signal. A first delay is determined based on portions of the input and output signals captured during static operation of the power supply and a second delay is determined based on portions of the input and output signals captured during dynamic operation. A delay mismatch is estimated based on a difference between the first and second delays.

Abstract: A circuit arrangement includes a component having a closed signal path, that closed signal path connected to a first port, a second port and at least a third port. The component has a directed signal flow of a signal applied to one of that ports. Such a coupling device can be connected to a transmitter and to a receiver path, respectively.

Abstract: A power amplifier (PA) envelope power supply and a process to select a converter operating mode of the PA envelope power supply are disclosed. The PA envelope power supply operates in one of a first converter operating mode and a second converter operating mode. The process for selecting the converter operating mode is based on a selected communications mode of a radio frequency (RF) communications system, a target output power from RF PA circuitry of the RF communications system, and a direct current (DC) power supply voltage.

Abstract: Systems, methods and apparatus a provided for calibrating actual output power of a transmit power sensor for closed loop power control using a quality metric such as error vector magnitude (EVM) to improve power detection accuracy. In aspects, a method for correlating an output of a transmit power sensor with actual output power of a wireless transmitter includes deriving a characteristic correlation between an actual output power of a set of transmit amplifiers and an output power and of a set of corresponding power detection circuits over a range of transmit power levels in a corresponding set of wireless devices; storing the characteristic correlation in a wireless device that is not part of the set from which the characteristic correlation was derived; and sensing an output of a transmit power sensor of the device while the transmitter of the device transmits according to one or more gain settings.

Abstract: In one embodiment a mixed-signal adaptive integrated circuit is comprised of a pre-distortion circuit operable to receive an RF input signal and to add a pre-distortion signal to the RF input signal to thereby provide a pre-distorted RF input signal, and a power amplifier coupled to the pre-distortion circuit and operable to receive the pre-distorted RF input signal and to provide an amplified RF output signal. The circuit further comprises a compensation module operable to receive the RF input signal and to provide a compensation signal, an auxiliary amplifier coupled to the compensation module and operable to selectively add the compensation signal to the amplified RF output signal, and a signal analyzer operable to receive and process the RF input signal and an RF output feedback signal to generate a first digital control signal for the pre-distortion circuit and a second digital control signal for the compensation module.

Abstract: A power amplifier (PA) envelope power supply, which provides an envelope power supply signal to radio frequency (RF) PA circuitry, and a process to prevent undershoot of the PA envelope power supply is disclosed. The process includes determining if an envelope control signal to the PA envelope power supply has a step change from a high magnitude to a low magnitude that exceeds a step change limit. Such a step change may cause undershoot of the PA envelope power supply. As such, if the step change exceeds the step change limit, the envelope control signal is modified to use an intermediate magnitude for period of time. Otherwise, if the step change does not exceed the step change limit, the envelope control signal is not modified.

Abstract: Systems and methods for measuring transmitter and/or receiver I/Q impairments are disclosed, including iterative methods for measuring transmitter I/Q impairments using shared local oscillators, iterative methods for measuring transmitter I/Q impairments using intentionally-offset local oscillators, and methods for measuring receiver I/Q impairments. Also disclosed are methods for computing I/Q impairments from a sampled complex signal, methods for computing DC properties of a signal path between the transmitter and receiver, and methods for transforming I/Q impairments through a linear system.

Abstract: Functionality can be implemented to calibrate the output transmit power of a power amplifier of a network device without the use of test equipment. An RF signal can be transmitted at the saturated output power (of a power amplifier) from a transmitter unit to a receiver unit of the network device via a loopback path. A received power of the RF signal received via the loopback path can be measured. The loopback gain associated with the network device is determined based on the saturated output power and the measured received power. The output transmit power can be calibrated by iteratively decreasing the output transmit power by an unknown value, transmitting a new RF signal via the loopback path at the decreased output transmit power, measuring the new received power, and calculating the decreased output transmit power using the loopback gain and the measured new received power.

Abstract: Systems and method for implementing a transmitter with hybrid closed loop power control in a communication device.

Abstract: A charge pump of a PA bias power supply, PA bias circuitry, and a process to optimize efficiency of the PA bias power supply are disclosed. The charge pump operates in one of multiple bias supply pump operating modes, which include at least a bias supply pump-up operating mode and a bias supply bypass operating mode. The process prevents selection of the bias supply bypass operating mode unless a DC power supply voltage is adequate to allow the PA bias circuitry to provide minimum output regulation voltage at a specified current. Otherwise, the bias supply pump-up operating mode is selected. The charge pump operates more efficiently in the bias supply bypass operating mode than in the bias supply pump-up operating mode; therefore, selection of the bias supply bypass operating mode, when possible, increases efficiency.

Abstract: Disclosed is an analog-digital converter which includes a pre-amplifier configured to output a comparison result between a sampled analog input signal and a reference signal and to control a power supply operation in response to a power control signal; a digital signal processor configured to generate a digital signal based on the comparison result; a power controller configured to generate an amplifier operation clock signal for controlling the pre-amplifier; and a counter configured to count the number of falling edges of the amplifier operation clock signal and to detect a power interruption point of time of the pre-amplifier according to the counted falling edge number. The power controller generates the power control signal for interrupting a power to be supplied to the pre-amplifier when the power interruption point of time of the pre-amplifier is detected.

Abstract: A method for link adaptation at a base station using metric feedback is disclosed. The method can include the steps of communicating with a mobile station over a communication link having one or more sub-channels and during the communication, receiving from the mobile station information relating to one or more mutual information per coded bit metrics for one or more candidate modulation types. The mutual information per coded bit metrics can be based on channel state knowledge of the sub-channels. Also, based on the received information, the operational performance of the mobile station can be predicted in view of one or more transmission parameters and performance factors and one or more of the transmission parameters can be selected based on a transmission condition of the communication link.

Abstract: A wireless device includes a channel covariance matrix calculating unit that calculates a covariance matrix based on a channel matrix estimated based on radio signal transmitted from a transmitting station. The wireless device further includes a first metric calculating unit that calculates a first metric based on the calculated covariance matrix. The wireless device further includes a W1 determining unit that calculates a first precoding matrix common to a plurality of bands based on the calculated first metric. The wireless device further includes second metric calculating units that calculate a second metric using the calculated first precoding matrix. The wireless device further includes an optimal CQI/PMI/RI determining unit that calculates a second precoding matrix of each band based on the calculated second metric.

Abstract: An efficient way to store backoff and crestcomp parameters while providing quick access to the backoff and crestcomp parameters associated with specific transmission configurations is described herein. A long-term memory stores amplifier parameters for a plurality of different transmission configurations. A selection element selects from the long-term memory a graph of the amplifier parameters corresponding to a selected subset of the transmission configurations. The selected graph relates each of a plurality of enhanced data channel gain ratios to a corresponding amplifier parameter. The selection element transfers the selected graph from the long-term memory to a fast memory proximate a DSP. Further, the selection element reselects and transfers new graphs into the fast memory as needed.

Abstract: A system comprising a pre-power amplifier and a hardware device which is configured to predistort an amplitude input signal by comparing interpolated data places, determined by comparing the input signal with data from a LUT, coming from a LUT with the amplitude input signal and choosing the closest input data place to the amplitude input signal to produce an amplitude predistortion output signal. The LUT contains predistortion data associated with the pre-power amplifier. The amplitude input signal is multiplied and scaled prior to being compared with the data in the LUT. A second LUT is used to predistort a phase input signal and the phase predistortion output signal is combined in the pre-power amplifier with the amplitude predistortion output signal. The system may be implemented in a mobile communications device.

Abstract: A power efficient, small-packaged radio frequency (RF) transmitter for use in avionics applications. The RF transmitter utilizes Cartesian feedback to operate a power amplifier with Class AB biasing and efficiency, while delivering Class A biasing performance. The RF transmitter includes interstage pads and high pass filters specially configured to meet demanding requirements for both adjacent channel power (ACP) limits and wideband spurious energy limits. The RF transmitter is much smaller in size and dissipates less DC power and heat than previous RF transmitters used in avionics applications.

Abstract: A communications device is disclosed that includes a united integrated circuit card (UICC) that provides a single wire protocol (SWP) current signal to a near field communications (NFC) device. The SWP current signal is filtered by a filter to remove noise from the SWP current signal. The filter is precharged by a reference voltage when the SWP current signal is in a low state and then filters the SWP current signal when the SWP current signal is in a high state. A switching network provides the filter with the reference voltage to precharge when the SWP is current signal is in the low state and then provides the filter with the SWP current signal to filter when the SWP current signal is in the high state.

Abstract: This disclosure relates to linearization in polar modulators of wireless communication devices, to attain linear amplification and high power efficiency during transmission.

Abstract: Provided are an RFID reader and a method for suppressing transmission leakage signals thereof. The RFID reader includes a first loop, a second loop, and a digital signal processor. The first loop suppresses a first transmission leakage signal of an RX signal in response to a first leakage control signal. The second loop suppresses a second transmission leakage signal of the RX signal, received through the first loop, in response to a second leakage control signal. The digital signal processor generates the first leakage control signal and the second leakage control signal. The digital signal processor generates the first leakage control signal until the level of the first transmission leakage signal becomes equal to or lower than the level of a first reference transmission leakage signal.

Abstract: An embodiment of the invention provides an electronic device. The electronic device includes a digital-to-analog converter (DAC), a transmitter front-end (TX FE), an amplifier, an analog-to-digital converter (ADC), and a swap circuitry. The TX FE has a first and a second input end coupled to a first and a second output end of the DAC, respectively. The ADC has a first and a second input end coupled to a first and a second output end of the amplifier, respectively. The swap circuitry is configured to couple the first and second output ends of the DAC to a first and a second input end of the amplifier in a normal state, respectively, and couple the first and second output ends of the DAC to the second and first input ends of the amplifier in a swapped state, respectively.

Abstract: Provided is a transmission circuit that operates highly efficiently by avoiding deterioration of the linearity of an output signal and suppressing occurrence of distortion of the output signal, when using the envelope tracking method. In this transmission circuit, offset control section (160) sets voltage that makes the corrected envelope signal level equal to or higher than the delayed envelope signal level, as offset voltage. By this means, the corrected envelope signal level becomes equal to or higher than the delayed envelope signal level, so that it is possible to prevent the power supply voltage from being lower than the optimal power supply voltage, making it possible to prevent the linearity of an output signal from deteriorating in power amplifier (130).

Abstract: Systems and methods for measuring transmitter and/or receiver I/Q impairments are disclosed, including iterative methods for measuring transmitter I/Q impairments using shared local oscillators, iterative methods for measuring transmitter I/Q impairments using intentionally-offset local oscillators, and methods for measuring receiver I/Q impairments. Also disclosed are methods for computing I/Q impairments from a sampled complex signal, methods for computing DC properties of a signal path between the transmitter and receiver, and methods for transforming I/Q impairments through a linear system.

Abstract: A distortion compensation device includes a distortion compensator that predistorts an input signal based on delay signals and distortion compensation coefficients corresponding to the respective delay signals obtained by applying different amounts of delay to the input signal, a calculator that calculates an error signal based on the predistorted input signal and an output signal from an amplifier that amplifies the predistorted input signal, a calculator that calculates prospective distortion compensation coefficients for updating the distortion compensation coefficients, based on the error signal, a saturation processor that performs saturation processing for bringing, when the prospective distortion compensation coefficients do not fall into a preset range, the prospective distortion compensation coefficients into the preset range, and a controller that controls the updating of the distortion compensation coefficients based on pieces of coefficient saturation information indicating whether the saturation

Abstract: Systems and methods for compensating for non-linearity of a non-linear subsystem using predistortion are disclosed. In one embodiment, a system includes a non-linear subsystem and a predistorter configured to effect predistortion of an input signal of the non-linear subsystem such that the predistortion compensates for a non-linear characteristic of the non-linear subsystem. The system also includes an adaptor that adaptively configures the predistorter based on a feedback signal that is representative of an output signal of the non-linear subsystem and an input signal that is representative of the input signal of the non-linear subsystem. The adaptor generally models the non-linear subsystem as a concatenation of a non-linear model that corresponds to the non-linear characteristic of the non-linear subsystem and a linear model that corresponds to a known linear characteristic of the non-linear subsystem.

Abstract: A transmitter (50) includes a nonlinear predistorter (58) having two instances of an inverting transform (106, 106?) that may be implemented in a look-up table (122) and that implements a transform which is the inverse of an average terms component (96) of a nonlinear transform model (94) for an amplifier (70). The look-up table (122) may be updated using a continuous process control loop that avoids Cartesian to polar coordinate conversions. One of the two instances of the inverting transform (106) is cascaded with a non-inversing transform (108) within a residual cancellation section (110) of the predistorter (58). The non-inversing transform (108) implements a transform which is an estimate of a deviation terms component (98) of the nonlinear transform model (94). The residual cancellation section (110) produces a weak signal that replaces an unwanted residual term in an amplified communication signal (76) with a much weaker residual term.