Abstract: Distortion and aliasing reduction for digital to analog conversion. Synthesis of one or more distortion terms made based on a digital signal (e.g., one or more digital codewords) is performed in accordance with digital to analog conversion. The one or more distortion terms may correspond to aliased higher-order harmonics, distortion, nonlinearities, clipping, etc. Such distortion terms may be known a priori, such as based upon particular characteristics of a given device, operational history, etc. Alternatively, such distortion terms may be determined based upon operation of a device and/or based upon an analog signal generated from the analog to conversion process. For example, frequency selective measurements made based on an analog signal generated from the digital to analog conversion may be used for determination of and/or adaptation of the one or more distortion terms. One or more DACs may be employed within various architectures operative to perform digital to analog conversion.

Abstract: Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Abstract: A method of providing frequency dependent signal attenuation. An RF input signal is split into a first signal portion and a second signal portion. Discrete time filtering, a negative group delay and bandstop filtering are applied to the first signal portion to provide a filtered signal portion. The second signal portion is applied to a component, and a component output signal portion is received from the component. The component output signal portion is combined with the filtered signal portion to provide an RF output signal having frequency dependent attenuation.

Abstract: Systems and techniques relating to wireless communications are described.

Abstract: This invention includes a waveform analyzing means (13) for calculating an estimated value of a back-off value required by a power amplifier (2), which amplifies a high-frequency signal generated from a baseband signal (I, Q) to a predetermined transmission power, by analyzing the waveform of the baseband signal (I, Q), and a control means (14) for controlling at least one of the amplitude of high-frequency power input to the power amplifier (2) and the supply power of the power amplifier (2) on the basis of the estimated value. The invention calculates the estimated value of a back-off value by analyzing the waveform of a baseband in this manner, and hence need not generate a table in advance by calculating a back-off value for each combination of code channels. The invention can therefore be applied to even a case in which the number of code channels greatly increases, and can effectively prevent an increase in adjacent channel leakage power due to a signal obtained by multiplexing these code channels.

Abstract: A communication system is provided, including an antenna, a PA, a linearization circuit to enhance linearity, a filter system, and a controller. The controller is configured to receive information on the signals and conditions, and based on the information the controller controls one or more of the antenna, the PA, the linearization circuit and the filter system to provide an optimum configuration to meet specifications of signal properties under the conditions. The controller may look up a registry having entries regarding the specifications of signal properties under conditions in terms of predetermined parameters.

Abstract: A radio frequency communication system and a noise isolation method applied to the radio frequency communication system are provided. The radio frequency communication system includes an antenna, an amplifier and a noise isolating unit. The amplifier is electrically connected to the antenna to amplify a common-mode signal transmitted by the antenna and outputs an amplified common-mode signal. The noise isolating unit is electrically connected to the amplifier to isolate the amplified common-mode signal. The noise isolating unit includes a first transformer and a second transformer. The noise isolating unit isolates the common-mode signal and transmits the differential-mode signal, which can effectively reduce the noise and improve a signal to noise ratio without affecting the original signal.

Abstract: A technique for a reconditioning equalizer filter for non-constant envelope signals is described. The input to a transmitter chain is modified by a reconditioning equalizer filter, prior to being applied to the transmitter. The reconditioning equalizer filter modifies and smoothens the amplitude of the signal. The modified and smoothened signal has its peaks reduced which results in lower Crest Factor. The input to the reconditioning equalizer filter could be a baseband, intermediate frequency (IF) or radio frequency (RF) signal. When the signal is an IF or RF signal, it needs to be down-converted to baseband before being applied to the reconditioning equalizer filter. The reconditioning equalizer filter could be performed in a digital or analog domain.

Abstract: Apparatus and methods for envelope tracking calibration are provided. In one embodiment, a method of calibrating an envelope tracker having an envelope shaping table generated at a desired gain compression of a power amplifier is provided. The method includes generating a supply voltage for the power amplifier using the envelope tracker, operating the supply voltage of the power amplifier at a first voltage level associated with substantially no gain compression of the power amplifier, and measuring an output power of the power amplifier at the first voltage level. The method further includes decreasing a voltage level of the supply voltage one or more times and measuring the output power at each voltage level, determining a second voltage level of the power amplifier associated with a gain compression equal to about that of the desired gain compression, and calibrating the envelope tracker based on the determination.

Abstract: A power amplifier system including a composite digital predistorter (DPD) ensuring optimized linearity for the power amplifier is described. In this system, a digital-to-analog converter (DAC), an analog filter, a first mixer, and the power amplifier are serially coupled to the composite DPD. A second mixer, a receive gain block, and an analog-to-digital converter (ADC) are serially coupled to the output of the power amplifier. A DPD training component is coupled between the inputs of the composite DPD and the ADC. The composite DPD includes a memory-based DPD, e.g., a memory polynomial (MP) DPD, a memoryless-linearizing DPD, e.g., a look-up table (LUT) DPD, and two multiplexers.

Abstract: A communication apparatus (200) has a calibration mode in which a signal is passed through circuitry (30, 80) of the apparatus, and a controller (160) measures the response of the circuitry (30, 80) to the signal and adjusts the circuitry (30, 80) to improve performance. The signal used for calibration has a wider bandwidth than the bandwidth of signals used for transmission. The wider bandwidth may be provided by reconfiguring a digital filter (20) from low-pass to high-pass.

Abstract: An apparatus and a method for operating a memory compensation Digital Pre-Distortion (DPD) are provided. In the method for operating a memory compensation DPD system, an input signal is received. An input average power of the input signal is determined. When the input average power of the input signal belongs to a non-linear section of the input average power, DPD is performed on a previous signal corresponding to a memory degree set depending on at least one non-linear section of the input average power.

Abstract: Aspects of a method and system for estimating and compensating for non-linear distortion in a transmitter using calibration are presented. Aspects of the system may include one more circuits that may enable estimation, within a single IC device, of distortion in output signals generated by a transmitter circuit. The circuitry may enable compensation of the estimated distortion by predistorting subsequent input signals. The transmitter circuit may generate subsequent output signals based on the predistorted subsequent input signals.

Abstract: Radio frequency (RF) power amplifier (PA) circuitry, which transmits RF signals is disclosed. The RF PA circuitry includes a final stage, a final stage current digital-to-analog converter (IDAC), and a final stage temperature compensation circuit. A final stage current reference circuit may provide an uncompensated final stage reference current to the final stage temperature compensation circuit, which receives and temperature compensates the uncompensated final stage reference current to provide a final stage reference current. The final stage IDAC uses the final stage reference current in a digital-to-analog conversion to provide a final stage bias signal to bias the final stage. The temperature compensation provided by the final stage temperature compensation circuit is selectable.

Abstract: [Problem] To provide an amplifier and an amplification method in which degradation in the quality of the output signal is reduced.

Abstract: Method for calibrating a linearizer and linearized electronic component the method comprises predistortion, in a predistortion linearizer, of a signal upstream of an electronic component to compensate nonlinear distortion. Determining predistortion setting parameters comprises applying a bifrequency test signal to the component and measuring the relative amplitudes of the lines at the output of the component. A variable indicative of the magnitude |Kp| of the AM/PM conversion coefficient of the component is calculated on the basis of these measurements. The predistortion setting parameters are adjusted so as to minimize |Kp|. The method may in particular be implemented in a linearized amplifier device and in an amplifier test bench.

Abstract: The transmission path of a communication device includes, in part, N upconverters each of which receives M phases of a signal to be transmitted. Each upconverter further receives one of N sets of phases of a LO signal. Each of the N sets includes M phases of the LO signal. The communication device further includes at least one combiner, and N amplifiers each responsive to a different one of the N upconverters to generate N amplified signals. The combiner combines the N amplified signals to generate an output signal. By selecting the gain of one of the amplifiers to be different than the gain of the remaining amplifiers, the undesired harmonics of the signal to be transmitted, caused by non-linearity of the amplifiers, is reduced. Each upconverter optionally includes a multitude of upconverters whose outputs are combined to further reduce the spurious harmonic upconversion products and the counter-intermodulation distortion (IM3).

Abstract: To estimate complex factors for use in predistortion of a power amplifier, a complex factor is selected a set of complex factors a computation interval. A solution value is estimated for the selected complex factor during the computation interval by an iterative computation that constrains the estimated solution value towards a final solution value over an arbitrary number of iterations that is not bounded by the duration of the computation interval. A cumulative error in the estimated solution value is computed at each iteration over consecutive computation intervals. From the cumulative error, it is determined whether a convergence criterion is met and, if so, the estimating is terminated. The termination occurs independently of the solution value estimated for any one of the complex factors in the set.

Abstract: The embodiments of the present invention provide a predistortion device, method for predistortion and transmitter/receiver system. The predistortion device comprises a predistortion unit, and the predistortion device further comprises: a signal acquiring unit to process the output signals of a transmitting circuit to obtain distorted signals; a signal coupling unit to couple the distorted signals acquired by the signal acquiring unit to the receiving signals inputted to a receiving circuit; and a signal processing unit to decouple the output signals of the receiving circuit to acquire the distorted signals and the receiving signals. With the embodiments of the present invention, an analog receiving circuit may be reused in a half duplexing system and a full duplexing system, and the requirement on the analog receiving circuit is lowered, thereby reducing the cost.

Abstract: A digital, radio frequency (RF) power amplifier includes first and second RF digital to analog converters (RF DACs) and a combiner to combine output signals of the first and second RF DACs. In at least one embodiment, the digital RF power amplifier may be operated in any of a number of different operating modes by appropriately generating amplitude and phase input signals for the first and second RF DACs. A mode of operation may be selected for the digital RF power amplifier based, at least in part, on a desired average output power level of the power amplifier.

Abstract: In one embodiment, an amplifier system has a tap, a delay filter, a linearized amplifier, and a hybrid combiner. The tapped portion of an input signal is amplified by the amplifier, the untapped portion of the input signal is delayed by the delay filter, and the combiner combines the resulting amplified, tapped portion and the delayed, untapped portion to generate an amplified output signal. By re-combining the delayed, untapped portion of the input signal with the amplified, tapped portion, the power of the untapped portion is not lost, and the amplifier does not have to compensate for all of the distortion that would otherwise be associated with the total output power level. Such an amplifier system is applicable, for example, in upgrading an existing GSM cell site to support both GSM communications as well as UMTS communications without degrading GSM operations.

Abstract: An apparatus configured to couple to a plurality of subscriber lines comprising a plurality of transmitters configured to couple to a plurality of physical channels and at least one virtual channel. The number of physical channels equals the number of subscriber lines. A processor is configured to compute a precoder matrix to minimize an error value. The error value accounts for an error on each channel subject to a constraint on power for each channel. A precoder is coupled to the processor and configured to use the precoder matrix to jointly process a plurality of data signals to generate a plurality transmit signals for the plurality of physical channels and the at least one virtual channel.

Abstract: A signal processing apparatus includes a corrector that corrects a digital signal in accordance with a correction value, a converter that converts the digital signal corrected by the corrector into an analog signal, a sample-and-hold unit that holds an instantaneous value of the analog signal that has been obtained by the converter and that has been amplified by an amplifier for a certain frequency that is smaller than twice a maximum frequency of the analog signal, a digitizer that converts the instantaneous value held by the sample-and-hold unit into a digital value when the digitizer received an operation clock having the certain frequency, and an updater that updates, on the basis of the digital value obtained by the digitizer, the correction value of the corrector such that the correction value becomes a correction value that reduces nonlinear distortion in the analog signal amplified by the amplifier.

Abstract: Systems and methods for radio frequency digital predistortion in a multi-band transmitter are disclosed. In one embodiment, the multi-band transmitter includes a digital upconversion system configured to digitally upconvert digital input signals to provide digital radio frequency signals. Each digital input signal and thus each digital radio frequency signal corresponds to a different band of a multi-band transmit signal to be transmitted by the multi-band transmitter. The multi-band transmitter also includes a radio frequency digital predistortion system configured to digitally predistort the digital radio frequency signals to provide predistorted digital radio frequency signals, and a combiner configured to combine the predistorted digital radio frequency signals to provide a multi-band predistorted digital radio frequency signal.

Abstract: Methods and apparatus are provided for amplifying an input signal. An electronic circuit system comprises a first circuit comprising a power amplifier, configured to receive a first branch of an input signal, and generate a first amplified signal based on the input signal of the first branch; a second circuit, configured to receive a second branch of the input signal, generate a cancellation signal based on the input signal of the second branch, and combine the first amplified signal and the cancellation signal to generate a second amplified signal. The second circuit comprises an interference re-construction module, which is configured to model an inverse characteristic of residual distortion and interference of the first circuit via a predefined re-construction function, and generate an anti-phased interference signal based on the input signal of the second branch and the predefined re-construction function. The cancellation signal is generated from the anti-phased interference signal.

Abstract: A transmitter (32) generates a time-varying stabilized bias signal (82) from which sub-RF distortion signals (26, 29) have been cancelled. The distortion signals (26, 29) are byproducts of imperfect amplification and of biasing networks. An envelope amplifier (84) includes a high bandwidth differential input, linear, bias signal amplifier (120) and a low bandwidth switching amplifier (122) coupled together to achieve both a high bandwidth and high efficiency. A control loop (154) feeds a portion of the voltage V(t) from a conduction node (146) of the RF power amplifier (36) to one of the differential inputs of the linear bias signal amplifier (120), while a bias control signal (92) drives the other differential input. The portion of voltage V(t) fed to bias signal amplifier (120) is a low power portion from which the RF portion has been removed. A bias signal (128) may be predistorted to cancel distortion signals (26, 29).

Abstract: An open loop envelope tracking system calibration technique and circuitry are proposed. A radio frequency power amplifier receives a modulated signal. An envelope tracker power converter generates a modulated power amplifier supply voltage for the radio frequency power amplifier based on a control signal derived from the modulated signal. A first output power and a second output power of the radio frequency power amplifier are measured when the control signal is respectively delayed by a first delay period and a second delay period. A sensitivity of the output power of the radio frequency power amplifier is near a maximum near the first delay period and the second delay period. The first delay period and/or the second delay period are adjusted until the first output power substantially equals the second output power. The first delay period and the second delay period are used to obtain a calibrated fine tuning delay offset.

Abstract: To estimate complex factors for use in predistortion of a power amplifier, a complex factor is selected a set of complex factors a computation interval. A solution value is estimated for the selected complex factor during the computation interval by an iterative computation that constrains the estimated solution value towards a final solution value over an arbitrary number of iterations that is not bounded by the duration of the computation interval. A cumulative error in the estimated solution value is computed at each iteration over consecutive computation intervals. From the cumulative error, it is determined whether a convergence criterion is met and, if so, the estimating is terminated. The termination occurs independently of the solution value estimated for any one of the complex factors in the set.

Abstract: A method and apparatus for updating equalization coefficients of an adaptive pre-equalizer of a network element are provided. The method includes monitoring a communications channel to measure distortion of a communications signal received from the network element and detecting whether a transient impairment is present in the communication signal. When a transient impairment is not detected to be present, a pre-equalization coefficient update is transmitted to the network element. However, when a transient impairment is detected to be present, at least selected ones of the pre-equalization coefficients are scaled before the update is transmitted to the network element or the update is withheld from being transmitted to the network element. An apparatus is also disclosed.

Abstract: The disclosure relates to a method for improving the power consumption of a transmission chain by varying the operating point of a power amplifier to optimize (e.g., reduce) the current that is consumed by the amplifier. The operating point is varied by changing the bias voltage(s) (e.g., supply voltage, quiescent voltage) of the amplifier to a predetermined value that is chosen based upon the effect that a given transmitted signal modulation scheme characteristic (e.g., channel bandwidth and/or number of subcarriers) has on the operating point of a power amplifier.

Abstract: A transmitter (32) generates a time-varying stabilized bias signal (82) from which an amplifier-generated, sub-RF distortion signal (26) has been canceled. The distortion signal (26) is a byproduct of amplification and is generated due to imperfect linearity and/or other characteristics of a linear RF power amplifier (36). An envelope amplifier (84) includes a high bandwidth differential input, linear, bias signal amplifier (120) and a low bandwidth switching amplifier (122) coupled together to achieve both a high bandwidth and high efficiency. A control loop (154) feeds a portion of the voltage V(t) from a conduction node (146) of the RF power amplifier (36) to one of the differential inputs of the linear bias signal amplifier (120), while a bias control signal (92) drives the other differential input. The portion of voltage V(t) fed to bias signal amplifier (120) is a low power portion from which the RF portion has been removed.

Abstract: An amplifying device of an embodiment includes: a first amplifier amplifying a first component of an input signal; a first output circuit having an input connected to an output of the first amplifier and converting impedance seen from an output of the first output circuit to make the converted impedance seen from the first amplifier; a second amplifier amplifying a second component of the input signal with a bias deeper than that of the first amplifier; a second output circuit having an input connected to an output of the second amplifier, having a longer electrical length than that of the first output circuit part, and converting impedance seen from an output of the second output circuit to make the converted impedance seen from the second amplifier; and a combiner combining the first component amplified by the first amplifier and the second component amplified by the second amplifier.

Abstract: A power amplifier apparatus that includes a processor that performs a first distortion compensation processing on an input signal using a distortion compensation coefficient to obtain a first signal and an amplifier that amplifies the first signal. The processor performs a second distortion compensation processing the amplified signal using the distortion compensation coefficient to obtain a second signal and updates the distortion compensation coefficient to enable convergence between the first signal and the second signal.

Abstract: A transmitter (20) includes a peak reduction section (30), a predistorter (98), and an amplifying section (102) biased by a variable bias signal generator (118). The peak reduction section (30) is controlled by a signal magnitude threshold (36) that defines maximum magnitudes for local peaks (32) of a reduced-peak communication signal (38). The bias signal generator (118) is controlled by a bias control signal (110). Both the signal magnitude threshold (36) and the bias control signal (110) are derived from a common reduced bandwidth (50) peak-tracking signal (42). The peak-tracking signal (42) is derived from an inflated-peak communication signal (26). The predistorter (98) applies distortion to the reduced-peak communication signal (38) that is configured, at least in part, by the bias control signal (110).

Abstract: A method for detecting an ingress of a short wave radio signal in a power line communication system which determines a strength of a common mode signal at a frequency of the power line communication system during a time period when no communication in the power line communication system at this frequency takes place and an ingress is detected if the strength of the common mode signal is above a determined threshold. A corresponding power line communication modem can implement such a method.

Abstract: Digital baseband channel signals are received and up-sampled to a common sampling rate. The digital baseband channel signals are filtered using low pass filters. Complex frequency shifting is performed of the filtered digital baseband channel signals based on the associated different channel frequencies to obtain digital channel signals, which are combined to generate a digital wideband multi-channel signal that is a digital representation of an analog wideband multi-channel signal that is based on combining analog channel signals that correspond to the analog baseband channel signals. A non-linear pre-distortion of the digital wideband multi-channel signal is performed, the non-linear pre-distortion adding at least one of a gain and a phase shift to the digital wideband multi-channel signal such that the digital channel signals included within the digital wideband multi-channel signal are compensated for a non-linear distortion effected on the analog wideband multi-channel signal by a high-power amplifier.

Abstract: An antenna power coupler having a variable coupling factor is disclosed. In an exemplary embodiment, an apparatus includes a coupler configured to generate a power detection signal based on transmit signal power associated with a plurality of transmission technologies and a variable attenuator configured to apply a selected attenuation factor to the power detection signal to generate an adjusted power detection signal, the selected attenuation factor associated with a selected transmission technology.

Abstract: A method and system for determining adaptation parameters for pre-distorters in a multi-band power amplifier system of a communication system are disclosed. A method includes receiving, at an adaptor, a reference signal comprising a first plurality of signals having substantially overlapping frequency spectra. Each of the first plurality of signals is input to a corresponding one of a plurality of pre-distorters. The adaptor also receives an observation signal comprising a second plurality of signals tuned to substantially a same frequency to have overlapping frequency spectra. Each of the second plurality of signals is derived from an output of the multi-band power amplifier system. The adaptor computes the adaptation parameters based on the reference signal and the observation signal.

Abstract: A method and an apparatus for modifying a complex-valued signal are described, the complex-valued signal representing a first symbol and a second symbol. A signal trajectory of the complex-valued signal between the first and second symbols is determined, and, if the signal trajectory passes nearby the constellation origin, the signal trajectory is altered to run closer to the constellation origin.

Abstract: A radio frequency transmitter comprising a modem which receives one or more input data signals and an adaptive predistortion signal and provides a baseband in-phase signal and a baseband quadrature signal. The transmitter may comprise a power amplifier module which receives the in-phase and quadrature phase signals and provides a radio frequency output signal. A predistortion module receives the radio frequency signal, downconverts the radio frequency signal to an intermediate frequency signal, and downconverts the intermediate frequency signal to a baseband feedback signal. The transmitter samples the feedback signal and provides an adaptive predistortion signal to the modem.

Abstract: The present disclosure relates to amplitude based pre-distortion calibration of an RF communications terminal, such as a cell phone, by transmitting a first standard RF transmit burst from the RF communications terminal to an RF test instrument, which assimilates the first standard RF transmit burst. A calibration control system extracts information regarding the first standard RF transmit burst from the RF test instrument; determines amplitude based distortion of the RF communications terminal using the extracted information; determines amplitude based pre-distortion calibration information using the determined amplitude based distortion; and calibrates the RF communications terminal using the amplitude based pre-distortion calibration information. By using a single-shot transmit burst, calibration times may be minimized.

Abstract: A radio transmission system comprising: a first Volterra Engine (VE) linearizer; a second VE linearizer coupled to the first VE linearizer; and a power amplifier (PA) coupled to at least one of the VE linearizers. Each VE linearizer compensates for a different distortion or nonlinearity aspect of an output signal from the PA.

Abstract: An apparatus and method for a Time Alignment (TA) operation used by an Envelope Tracking (ET) Radio Frequency (RF) Power Amplifier (PA) that amplifies RF signals are provided. The ET RF PA has an input signal including complex, reference, and feedback signals. The apparatus includes a fast convolution unit for receiving the reference signal and the feedback signal, fore extracting respective envelopes of the reference signal and the feedback signal, for generating a cross-covariance vector for the reference signal envelope and the feedback signal envelope, a delay estimation unit for receiving the cross-covariance vector from the fast convolution unit, for determining peak values of the cross-covariance vector, for performing a fine time delay estimation, and for generating time delay settings according to the fine time delay estimation, and delay filters respectively delaying a timing of the reference signal and the feedback signal according to the generated time delay settings.

Abstract: A method and an apparatus for controlling a transmit signal of a radio frequency power amplifier are provided. The method includes: adjusting a power supply voltage of the power amplifier to an efficiency point power supply voltage under designated transmit power; querying correspondence between an input voltage and transmit power at each power level under the efficiency point power supply voltage; and adjusting, according to the correspondence, an input voltage to an input voltage corresponding to the designated transmit power. The embodiments of the present invention, the power amplifier is enabled to work at an optimum efficiency point while the transmit power of the power amplifier is under control, which improves efficiency of the power amplifier.

Abstract: A transmitter (70) generates a time-varying, detroughed, biasing signal (154) for an RF power amplifier (10) so that the RF power amplifier (10) is biased in accordance with an envelope tracking scheme. A trough-filling section (94) is responsive to an envelope tracking signal (86), which in turn is responsive to a magnitude signal (90) extracted from a complex baseband communication signal (76). The trough-filing section (94) includes a limiting stage (108) that forms a raw troughing signal (110) which expands the bandwidth of the envelope tracking signal (86). A filtering stage (116) reduces the bandwidth of the raw troughing signal (110) to form a trough-filling signal (122) that is combined back into the envelope tracking signal (86) using a linear process that maintains the bandwidth of the envelope tracking signal (86).

Abstract: Apparatus, methods and methods of manufacture are provided for the processing of a current mode signal. A first signal processing stage comprising at least one output terminal is configured to produce a current mode output signal. A mutual inductance stage is arranged to inductively couple the at least one output terminal of the first signal processing stage to at least one input terminal of a second signal processing stage, wherein an input signal is generated at the at least one input terminal of the second signal processing stage on the basis of the current mode output signal produced at the at least one output terminal of the first signal processing stage.

Abstract: A computational processor uses a binary signal, being a set of 1- or 0-valued elements of a same number as a number of elements in an input signal, to generate computational data whose elements are exclusive OR values between each element of the input signal and a corresponding element in the binary signal at a same position. The modulator 13 modulates the input signal and the computational data according to a primary modulation scheme, and generates primary-modulated signals. An IFFT calculator applies an inverse fast Fourier transformation to the primary-modulated signals to generate inverse transformation data. A transmitter generates a baseband signal based on generated inverse transformation data whose peak-to-average power ratio matches a standard, and generates and transmits a transmission signal from the baseband signal and data specifying computations conducted to generate the inverse transformation data that matches the standard.

Abstract: A high performance and cost effective method of RF-digital hybrid mode power amplifier systems with high linearity and high efficiency for multi-frequency band wideband communication system applications is disclosed. The present disclosure enables a power amplifier system to be field reconfigurable and support multiple operating frequency bands on the same PA system over a very wide bandwidth. In addition, the present invention supports multi-modulation schemes (modulation agnostic), multi-carriers and multi-channels.

Abstract: A system for implementing linearization of a radio frequency (RF) power amplifier (PA) in a base station, as well as various component circuitry for implementing said system. By means of a smart partitioning of the signal processing for predistortion between the analog domain and the digital domain, a more linear relationship between the digital input data and the output RF signal is achieved. Linearization of the PA's output signal is obtained using a mixed-signal apparatus. The digital baseband signal enters the RF signal source. The RF signal source comprises an in-band predistortion circuit, a micro-controller and digital modulator. The output of the digital modulator is an RF signal that enters the PA module. The PA module is composed of the PA and the RF power amplifier linearizer (RFPAL). The RFPAL comprises an RF predistortion circuit, and RF signal analyzer and a microcontroller. In addition, a backward data interface connects the RF signal source with the RFPAL.

Abstract: A method for compensating signal distortions in multiple transmitting branches entering a composite amplifier.