Abstract: An operation method of an electronic device includes determining whether a first communication module based on a first radio access technology (RAT) and a second communication module based on a second RAT operate in a connected state; determining whether a combination of a first band used by the first communication module and a second band used by the second communication module is a combination causing interference; and if the combination of the first band and the second band is a combination causing interference, transmitting a signal requesting to change one of the first band or the second band. The interference is caused by at least one transmission signal of the first RAT or at least one other signal derived from the at least one transmission signal.

Abstract: A radio frequency (RF) generator system includes first and second RF power sources, each RF power source applying a respective RF signal and second RF signal to a load. The first RF signal is applied in accordance with the application of the second RF signal. The application of the first RF signal is synchronized to application of the second RF signal. The first RF signal may be amplitude modulated in synchronization with the second RF signal, and the amplitude modulation can include blanking of the first RF signal. A frequency offset may be applied to the first RF signal in synchronization with the second RF signal. A variable actuator associated with the first RF power source may be controlled in accordance with the second RF signal.

Abstract: Apparatus and methods for power amplifier trimming based on coefficients for digital pre-distortion (DPD) are disclosed. In certain embodiments, a mobile device includes a transmit circuit that generates a plurality of digital transmit signals. The transmit circuit includes a plurality of DPD circuits each operable to provide DPD to a corresponding one of the digital transmit signals, a coefficient comparator circuit that generates a trimming control signal based on a plurality of coefficients of the plurality of DPD circuits, and a plurality of digital to radio frequency (RF) converters that convert the digital transmit signals into a plurality of RF signals. The mobile device further includes a front end system including a plurality of power amplifiers each amplifying a respective one of the RF signals, and a power amplifier trimming circuit that controls trimming of the power amplifiers based on the trimming control signal.

Abstract: This application relates to amplifier circuitry, in particular class-D amplifiers, operable in open-loop and closed-loop modes. An amplifier (300) has a forward signal path for receiving an input signal (SIN) and outputting an output signal (SOUT) and a feedback path operable to provide a feedback signal (SFB) from the output. A feedforward path provide a feedforward signal (SFF) from the input and a combiner (105) is operable to determine an error signal (?) based on a difference between the feedback signal and the feedforward signal. The feedforward comprises a compensation module (201) configured to apply a controlled transfer function to the feedforward signal in the closed-loop mode of operation, such that an overall transfer function for the amplifier is substantially the same in the closed-loop mode of operation and the open-loop mode of operation.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, an indication of a change in a non-linearity model associated with a power amplifier of the base station. The UE may update a model associated with the power amplifier based at least in part on the indication. The UE may further update at least one parameter associated with slicing received signals based at least in part on the indication. In some aspects, the UE may use at least two coefficients when slicing. Numerous other aspects are described.

Abstract: Disclosed are a solid-state microwave source and a branch consistency control method thereof. The branch consistency control method includes: collecting phase information of each branch unit under each of a plurality of preset target powers, and performing phase adjustment for each branch unit based on the phase information under each of the target powers; assembling coarsely-adjusted N branch units, a driver module, a power distribution module, a radial combiner, a circulator, and a waveguide coupler; adjusting a branch power by using the driver module and the power distribution module, to collect the phase information of each branch unit under each of the target powers; and when the phase information of each branch unit under each of the target powers meets a preset condition, performing phase adjustment for the branch unit based on the phase information.

Abstract: An autotuning controller is provided for improving power efficiency and linearity of digital power amplifiers (DPAs). The controller includes an interface including input and output terminals connected to the DPAs, the interface being configured to acquire input signals and output signals, a digital pre-distortion (DPD)-DPA adaptive controller including a processor and a memory running and storing a DPD algorithm, an efficiency enhancement method and a learning cost function.

Abstract: A new radio base station establishes a first and a second component. The first and second component carrier overlap each other. The base station transmits first synchronization signal blocks on the first component carrier. The base station transmits second synchronization signal blocks on the second component carrier interleaved in time with the first synchronization signal blocks.

Abstract: Examples relate to an amplification apparatus, device or method, to a Tap for a cable communication network comprising an amplification apparatus or device, and to a cable communication network comprising an amplification apparatus or device. The amplification apparatus comprises interface circuitry for exchanging a first version of a shared signal with a first component of the cable communication network. The shared signal is based on a frequency spectrum comprising at least a first frequency band and a second frequency band. The amplification apparatus comprises interface circuitry for exchanging a second version of the shared signal with a second component of the cable communication network. The amplification apparatus comprises amplifier circuitry configured to selectively amplify the first frequency band of the frequency spectrum of the shared signal, such that the first frequency band is amplified in the second version of the shared signal.

Abstract: Systems comprising a low power Digital Predistortion (DPD) system and methods of operation thereof are disclosed herein. In some embodiments, a system comprises a DPD system for digitally predistorting an input signal to provide an output signal. The DPD system comprises a DPD actuator comprising one or more configurable multiplication functions, each configurable to operate in different power modes. The different power modes comprise a first power mode in which the configurable multiplication function multiplies a first value related to an input sample of the input signal and a second value related to a respective DPD value to provide an output value and a second power mode in which the configurable multiplication function outputs, as the output value, are an approximation of a multiplication of the first value and the second value.

Abstract: Techniques are disclosed related to determining a modulation quality measurement of a device-under-test (DUT). A modulated signal is received from a source a plurality of times, and each received modulated signal is transmitted to each of a first vector signal analyzer (VSA) and a second VSA. The first VSA and the second VSA demodulate the received modulated signals to produce first error vectors and second error vectors, respectively. A cross-correlation calculation is performed on the first error vectors and second error vectors of respective received modulated signals to produce a complex-valued cross-correlation measurement, and a real component of the cross-correlation measurement is averaged over the plurality of received modulated signals. A modulation quality measurement is determined based on the averaged cross-correlation measurement.

Abstract: A wideband power amplifier (PA) linearization technique is proposed. A current interpolation technique is proposed to linearize power amplifiers over a wide bandwidth. The wideband power amplifier linearization technique employs a novel transconductance Gm linearizer using a current interpolation technique that achieves improvement in the third order intermodulation over wide bandwidth for a sub-micron CMOS differential power amplifier. By using a small amount of compensating bias into an opposite phase differential pair, linearization over wide bandwidth is achieved and can be optimized by adjusting the compensating bias.

Abstract: A sign switching circuitry is disclosed. In one aspect, the sign switching circuitry includes a first and second differential common-source amplifier having common differential input nodes and common differential output nodes configured such that a differential input signal applied at the common differential input nodes is amplified to a differential output signal at the common differential output nodes with a fixed gain by the first amplifier and by the fixed gain with opposite sign by the second amplifier. The sign switching circuitry also includes a switching circuitry configured to activate the first common-source amplifier and deactivate the second common-source amplifier to amplify the differential input signal by the fixed gain, and to activate the second common-source amplifier and deactivate the first common-source amplifier to amplify the differential input signal by the fixed gain with opposite sign.

Abstract: A power amplifier system includes: a drive stage configured to amplify an RF input signal and implemented in a substrate containing silicon; a power stage including a carrier amplifier configured to amplify a base signal from the RF input signal as amplified by the drive stage, and a peaking amplifier configured to amplify a peak signal from the RF input signal as amplified by the drive stage, the power stage being implemented in a substrate containing gallium arsenide; and a phase compensation circuit configured to change a phase of the RF input signal, wherein either the carrier amplifier or the peaking amplifier is connected to the phase compensation circuit.

Abstract: A distortion compensation device includes: a first distortion compensation circuit having a first distortion compensation characteristic for compensating for a first distortion occurring in an output of an amplifier, the first distortion compensation circuit being configured to compensate for the first distortion; a second distortion compensation circuit having a second distortion compensation characteristic for compensating for a second distortion occurring in the output of the amplifier, the second distortion compensation circuit being configured to compensate for the second distortion; and an update unit configured to update the second distortion compensation characteristic.

Abstract: A DPD (1) includes: a polynomial structure including a pseudo-interpolation/sub-sample-shift processing unit (101) configured to operate at a sampling rate for sampling an input signal not upsampled in a previous stage of the DPD (1), pseudo-interpolate a sample point between sample points of the input signal, and shift the pseudo-interpolated sample point by a sub-sample and a multiplexer (109) configured to select a combination of a sub-sample shift amount; and an FIR filter (107) configured to be provided in a subsequent stage of the polynomial structure and include a sub-sample delay filter delaying a sample point of the input signal by a sub-sample. The DPD (1) compensates for distortion due to a sample point of the input signal and compensates for distortion due to a sub-sample point between sample points of the input signal for the DPD (1), by using the polynomial structure and the FIR filter (107).

Abstract: Certain aspects of the present disclosure provide an amplification system. The amplification system generally includes: a first amplifier having an output coupled to an output of the amplification system; a second amplifier, inputs of the first amplifier and the second amplifier being coupled to an input of the amplification system; an impedance coupled to an output of the second amplifier; and a biasing circuit having a first voltage sense input coupled to the output of the first amplifier, a second voltage sense input coupled to the output of the second amplifier, and an output coupled to a bias input of the first amplifier.

Abstract: An electronic device configured to apply, to a first power amplifier (PA) input, one or more updated memory digital pre-distorter (mDPD) coefficient values is provided. The electronic device includes a processor; and a memory including a non-transitory computer readable storage medium storing instructions that, when executed, cause the processor to preload, from values stored in the memory of the electronic device, one or more mDPD coefficient values; transmit a training signal sequence while using the preloaded one or more mDPD coefficient values; receive the training signal sequence; update the one or more mDPD coefficient values based on the transmitted training signal sequence, the received training signal sequence, and the preloaded one or more mDPD coefficient values; and apply the updated one or more mDPD coefficient values to distort the first PA input.

Abstract: Embodiments of a calibration system for third order intermodulation distortion (IMD3) cancellation and a wireless apparatus are disclosed. In an embodiment, a calibration system for IMD3 cancellation includes a cancellation circuit for IMD3 cancellation between a first transmitter and a second transmitter, and a controller coupled to the cancellation circuit and configured to for each frequency channel of the first transmitter, perform a pre-conditional calibration of the cancellation circuit, after the pre-conditional calibration, determine a phase configuration for the cancellation circuit, and after the phase configuration for the cancellation circuit is determined, determine an attenuation configuration for the cancellation circuit.

Abstract: Various embodiments of the present disclosure relate to transmitter systems, methods, and instructions for signal predistortion.

Abstract: A RF generator includes a RF power source and a RF control module coupled to the RF power source. The RF control module is configured to generate at least one control signal to vary a respective at least one of an RF output signal from the RF power source or an impedance between the RF power source and a load. The RF output signal includes a RF signal modulated by a pulse signal, and the RF control module is further configured to adjust the at least one control signal to vary at least one of an amplitude or a frequency of the RF output signal or the impedance between the RF power source and the load to control a shape of the pulse signal. The at least one of the amplitude, the frequency, or the impedance is adjusted in accordance with respective feedforward adjustments that vary in accordance with a respective sensed pulse parameter detected between a matching network and the load.

Abstract: A circuit, method, and system including the circuit such that the circuit is for a passive radio-identification tag operating in a UHF band and is configured for radio communication with a reader which sends a periodic read signal. A period of the read signal includes an energy recovery phase and a communication phase. The circuit has: a control device configured to accumulate an energy reserve from the radio wave during the energy recovery phase and to communicate with the reader during the communication phase, an interface to connect an external analog sensor. The interface includes: an electrical connection configured to connect and supply the external analog sensor with electricity and to acquire the analog measurement from the sensor, an amplifier configured to amplify the signal of the analog measurement from the sensor, and an analog-digital converter configured to digitize the amplified analog measurement from the sensor.

Abstract: A combination amplifier can include a “main amplifier circuit” for signal amplification, and a matching “compensation amplifier circuit” to monitor distortion in the main amplifier output signal. The compensation amplifier circuit provides a compensation signal to the main amplifier circuit to compensate for and servo out distortion therein. The compensation amplifier circuit includes a passive input network and an amplifier. The passive input network can connect to both the input and output nodes of the main amplifier circuit such that the input and output signals cancel within the passive input network, leaving only the low level distortion component introduced in the main amplifier. Thus, the compensation amplifier is then only operating on the low-level distortion introduced in the main amplifier to generate the compensation signal. Because the compensation amplifier is then only operating on the very low distortion signal, any distortion it introduces into the compensation signal is negligible.

Abstract: A method, apparatus and computer program is described comprising: determining an absolute gain of a power amplifier over time, wherein the absolute gain is formed from the division of a feedback baseband signal derived (e.g. by demodulating an RF signal) from an output of the power amplifier, by a forward baseband signal that is used to form an input of the power amplifier; determining a relative gain transient response (GTR) of the power amplifier, by normalising the absolute gain to generate a relative gain of the power amplifier over time; and determining a transient response compensation value having inverse characteristics to the relative gain transient response.

Abstract: A signal adjustment device includes a frequency adjustment circuit, a filter circuit, and a power estimation circuit. The frequency adjustment circuit is configured to receive a two-tone signal from a signal generator and to generate a first signal according to the two-tone signal, wherein the signal generator generates the two-tone signal according to a first coefficient and a second coefficient. The filter circuit is configured to filter the first signal, in order to generate a second signal. The power estimation circuit is configured to detect a power of an intermodulation distortion from the third order signal component, which is associated with the two-tone signal, in the second signal, and to adjust at least one of the first coefficient and the second coefficient according to the power, in order to reduce the power.

Abstract: A distortion compensation device includes: a first predistorter configured to compensate for a distortion in an amplifier; and a second predistorter configured to compensate for the distortion in the amplifier, and update distortion compensation characteristics at a higher frequency than that of the first predistorter.

Abstract: Apparatus and methods for envelope alignment calibration in radio frequency (RF) systems are provided. In certain embodiments, calibration is performed by providing an envelope signal that is substantially triangular along an envelope path, and by providing an RF signal to a power amplifier along an RF signal path. Additionally, an output of the power amplifier is observed to generate an observation signal using an observation receiver. The observation signal includes a first peak and a second peak, and a delay between the envelope signal and the RF signal is controlled based on relative size of the peaks of the observation signal to one another.

Abstract: An apparatus and a method are provided for, in an electronic device which generates a reference signal having a reference frequency, mixes the reference signal to an input signal for transmission, and amplifies power, outputting a control signal for turning off amplifying the power, if a frequency of a signal acquired at an arbitrary point after generating the reference signal or mixing the signals before amplifying the power is out of a designated frequency band, thus preventing burnout of a power amplifier.

Abstract: Systems and methods are described to perform wireless communication. The device includes a pre-distortion circuit configured to pre-distort an input signal based on a parameter set including a plurality of coefficients and generate a pre-distorted signal, a power amplifier configured to amplify the pre-distorted signal and generate an output signal, and a parameter obtaining circuit configured to perform an iterative approximation operation based on the output signal and the pre-distorted signal, which change over time, according to an indirect training structure configured to minimize a difference between an intermediate signal obtained based on the output signal and the pre-distorted signal, and obtain the parameter set.

Abstract: An operation method of a relay operating in an in-band full duplex (IFD) scheme includes measuring a signal received from a source node during a first period; measuring a signal received from the source node and a signal received after being transmitted from the relay through a first beam during a second period, the second period being a period after a predetermined delay time from the first period; and calculating a self-interference (SI) amount of the first beam by comparing a measurement result during the second period with a measurement result during the first period.

Abstract: Some embodiments herein describe a radio frequency communication system that can include a transmitter to output an radio frequency (RF) transmit signal, the transmitter including a digital pre-distortion system (DPD) that pre-distorts the RF transmit signal. The DPD system can include a configurable non-linear filter, such as a Laguerre filter, having multiple rows where at least one row operates with a configurable decimation ratio. The DPD system can further include decimators and a crossbar switch coupled between the decimators.

Abstract: A circuit includes first and second gain stages and an output transistor. The second gain stage includes a transconductance amplifier and a variable impedance circuit coupled to an output of the transconductance amplifier. The variable impedance circuit is configured to implement a first impedance level at frequencies below a first frequency threshold and to implement a second impedance level at frequencies above a second frequency level. The first impedance level is larger than the second impedance level. The output transistor has a control input coupled to the variable impedance circuit. At frequencies above the second frequency threshold, the second impedance level is configured to be inversely related to current through the output transistor.

Abstract: Apparatus and methods provide predistortion for a phased array. Radio frequency (RF) sample signals from phased array elements are provided along return paths and are combined by a hardware RF combiner. Phase shifters are adjusted such that the RF sample signals are phase-aligned when combined. Adaptive adjustment of predistortion for the amplifiers of the phased array can be based on a signal derived from the combined RF sample signals.

Abstract: Remote compensators for mobile devices are provided. In certain embodiments, a mobile device includes a cable-side circulator, an antenna, receive amplifier circuitry that amplifies a receive signal from the antenna and provides an amplified receive signal to the cable-side circulator, transmit amplifier circuitry that amplifies a transmit signal from the cable-side circulator, and a first antenna-side circulator and a second antenna-side circulator each coupled between the transmit amplifier circuitry and the antenna. The first antenna-side circulator and the second antenna-side circulator operate to compensate the receive signal for transmit leakage arising from the transmit amplifier circuitry.

Abstract: Systems, circuitries, and methods for predistorting a digital signal in a transmit chain based on a predistortion function are provided. A method includes shifting a center frequency of an input signal by an offset to generate an adapted signal; predistorting the adapted signal based on a predistortion function to generate a predistorted adapted signal; reverting the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal; and causing transmission of the predistorted signal by a transmit chain.

Abstract: The present disclosure relates to a predistortion method and a predistortion system for a non-linear device-under-test, DUT. The predistortion method comprises the steps of: providing a reference input waveform to the DUT; deriving a predistorted waveform for the DUT based on the reference input waveform using an iterative direct digital predistortion technique; analyzing a relationship between the reference input waveform and the calculated predistorted waveform using a mathematical model; deriving a predistortion algorithm for the DUT based on said analysis; and applying said predistortion algorithm to an input signal and feeding the, thus, predistorted input signal to the DUT.

Abstract: Examples described herein provide a radio frequency circuit. The radio frequency circuit includes a controller; a parameter estimator circuit; a capture circuit; and a pre-distorter circuit. The pre-distorter generally includes one or more nonlinear filter circuits and configurable hardware circuitry. Each of the one or more the nonlinear filter circuits includes: adder(s); multiplier(s); and memories coupled to at least one of the adder(s) and the multiplier(s); where the configurable hardware circuitry is configured to distort one or more input signals by directing the one or more input signals along a path through the one or more adders, the one or more multipliers, and the one or more memories and by distorting the one or input signals using the nonlinear parameters stored in the one or more memories as the one or more input signals travels the path.

Abstract: An object is to provide a method and a system of adjusting a power amplifier which makes it possible to adjust a linearizer using signals of two carriers by the same power, to reduce the influence of the non-linearity on a multicarrier signal compared with the conventional. A method of adjusting a power amplifier, the power amplifier including a linearizer to reduce an intermodulation caused by non-linearity of the power amplifier, includes: inputting two signals generated by a signal generator into the power amplifier; measuring power of each order of first intermodulations of the two signals output from the power amplifier; calculating a power sum of second intermodulations by the plurality of signals using the measured power of each order of the first intermodulations; and adjusting the linearizer so that the power sum of the second intermodulations by the plurality of signals takes a minimum value or at most a predetermined value.

Abstract: An audio processor circuit includes a storage circuit, a digital-to-analog converter circuit, and an amplifier circuit. The storage circuit is configured to store digital audio data from an electrical device. The digital-to-analog converter circuit is configured to convert the digital audio data from the storage circuit into an analog audio signal. The amplifier circuit is configured to provide an output audio signal to an audio playing circuit according to the analog audio signal. If a total data volume of the digital audio data stored in the storage circuit is not a multiple of a throughput or the total data volume of the digital audio data stored in the storage circuit is equal to or greater than an upper limit value, the amplifier circuit is turned off such that the amplifier circuit stops providing the output audio signal to the audio playing circuit.

Abstract: Apparatus and method for linearizing narrowband carriers with low resolution predistorters are provided. The method includes amplifying, using a power amplifier, one or more broadcast carriers and linearizing, using a predistorter coupled to the power amplifier, the one or more broadcast carriers. The method also includes determining, using an electronic processor, a composite bandwidth of the one or more broadcast carriers and determining, using the electronic processor, whether the composite bandwidth is below a modulation bandwidth of the predistorter. The method further includes controlling, using the electronic processor, a pacification carrier generator coupled to the electronic processor to combine a pacification carrier with the one or more broadcast carriers when the composite bandwidth is below the minimum modulation bandwidth of the predistorter.

Abstract: A multichannel transmission system which includes a calibration functionality that allows precise calibration of the frequency conversion chains and of the multiport amplifier of the system to be performed without interruption of service. The proposed calibration makes it possible to correct the defects over the entire frequency band of the system.

Abstract: An amplifying circuit is provided. The amplifying circuit includes a bias circuit receiving an operating voltage from a power supply circuit and generating a first bias voltage, a resistance circuit connected between the bias circuit and a gate node and transferring the first bias voltage to the gate node, a start-up circuit generating a high-level start-up voltage and supplying the start-up voltage to the gate node before the operating voltage is supplied, based on a control signal, and an amplifier started-up by receiving the start-up voltage and then receiving the operating voltage and the first bias voltage to amplify a high frequency signal input through the gate node.

Abstract: An envelope tracking (ET) power amplifier apparatus with predistortion includes an amplifier circuit configured to amplify a radio frequency (RF) signal based on an ET voltage and a tracker circuit configured to generate the ET voltage based on an ET target voltage. The amplifier circuit may introduce phase and amplitude distortions to the signal being amplified. To offset such distortions, exemplary aspects of the present disclosure add an isogain predistortion circuit in an ET integrated circuit (IC) to correct for amplitude distortions and add a phase modulation predistortion circuit to correct for phase distortions.

Abstract: The present invention is directed to a CATV & MoCA® device, such as a passive, point of entry (POE) splitter or a RF amplifier. In the passive, POE splitter, a resistive splitter network connects plural “MoCA® only” ports, e.g., four, five or eight, to two or more “MoCA® and CATV” ports. The MoCA® only ports and MoCA® and CATV ports are connected to a MoCA® rejection filter, which is in turn connected to an input connected to a service provider. In the passive, POE splitter or the RF amplifier, an intuitive female coaxial port layout and marking scheme assists technicians with correctly connecting the POE splitter or RF amplifier to the correct coaxial cables at a customer's premises. The port layout also simplifies the circuitry design parameters on a printed circuit board (PCB) by orienting the “CATV & MoCA®” output ports at similar distances from a CATV input port of the POE splitter or RF amplifier.

Abstract: Provided is a power amplifier circuit that reduces the effect of intermodulation distortion without necessarily increase in the circuit size. The power amplifier circuit includes a first amplifier that amplifies a first signal and output a second signal, an extraction circuit that extracts a second-harmonic wave included in the second signal, a phase adjustment circuit that adjusts the phase of the extracted second-harmonic wave, and a power combiner that combines the second-harmonic wave of the adjusted phase with a third signal and output the first signal.

Abstract: A RF-digital hybrid mode power amplifier system for achieving high efficiency and high linearity in wideband communication systems is disclosed. The present invention is based on the method of adaptive digital predistortion to linearize a power amplifier in the RF domain. The power amplifier characteristics such as variation of linearity and asymmetric distortion of the amplifier output signal are monitored by the narrowband feedback path and controlled by the adaptation algorithm in a digital module. Therefore, the present invention could compensate the nonlinearities as well as memory effects of the power amplifier systems and also improve performances, in terms of power added efficiency, adjacent channel leakage ratio and peak-to-average power ratio. The present disclosure enables a power amplifier system to be field reconfigurable and support multi-modulation schemes (modulation agnostic), multi-carriers and multi-channels.

Abstract: A signal transmission device, including a RF processing circuit and a cable connecting circuit including a first choke inductor, a first and second bypass capacitors, and a first coupling capacitor, is provided. One end of the first choke inductor is coupled to a transceiver end of a RF transceiver and the other end is coupled to a first control end of a RF antenna controller. The transceiver end is coupled to a first conductor. The first bypass capacitor is coupled between the other end and a digital ground terminal. The first coupling capacitor is coupled between the digital ground terminal and a RF ground terminal. The second conductor is coupled to the RF ground terminal and a second control terminal of the RF antenna controller at a second connecting end of a RF cable. The second bypass capacitor is coupled between the second control terminal and the digital ground terminal.

Abstract: A system for time aligning widely frequency spaced signals includes a digital predistortion (DPD) processor and a power amplifier coupled to the DPD processor and operable to provide a transmit signal at a power amplifier output. The system also includes a feedback loop coupled to the power amplifier output. The feedback loop comprises an adaptive fractional delay filter, a delay estimator coupled to the adaptive fractional delay filter, and a DPD coefficient estimator coupled to the delay estimator.

Abstract: Methods and apparatus for selecting operating modes in a device are disclosed. In an embodiment, a method includes powering on a device that is configured to operate in safe and normal operating modes, detecting whether the device enters the normal operating mode within a time interval, and enabling the device to operate in the safe operating mode when the device does not enter the normal operating mode within the time interval. In an embodiment, an apparatus includes a power signal controller that powers on a device that is configured to operate in safe and normal operating modes, a state machine that detects whether the device enters the normal operating mode within a time interval, and a control signal controller that enables the device to operate in the safe operating mode when the device does not enter the normal operating mode within the time interval.

Abstract: The disclosed technology relates generally to semiconductor devices, and more particularly to power semiconductor devices in which effects of charge trapping are compensated. A radio frequency (RF) power transmitter system comprises a RF power semiconductor device that outputs a time-varying gain characteristic from a RF signal input waveform originating from a digital input, wherein the time-varying gain characteristic includes a gain error associated with charge-trapping events having a memory effect on the RF power semiconductor device lasting longer than 1 microsecond. The RF power transmitter system further comprises circuitry configured to apply an analog gate bias waveform to the RF power semiconductor device based on the time-varying gain characteristic to reduce the gain error.