Abstract: Provided is a modeling device performing calculation using an amplifier model that models an amplifier of which an internal state affecting a distortion characteristic varies, wherein the amplifier model includes a plurality of calculation models that model the amplifier in different internal states, and a combiner that combines the plurality of calculation models at a combination ratio corresponding to the internal state that varies.

Abstract: A device, method, and system for signal distortion pre-correction, and a composite system are disclosed. The device-includes: a signal distortion correction network module, a correction parameter trainer, a data collection module connected to an external power amplifier module, and a first conversion module. The data collection module is configured to perform time-division collection on output signals of channels of the power amplifier module and output analog feedback signals to the first conversion module. The first conversion module is configured to convert the analog feedback signals into digital feedback signals. The correction parameter trainer is configured to determine a correction parameter according to the digital feedback signals and a forward signal inputted. The signal distortion correction network module is configured to correct the forward signal based on the correction parameter and output a pre-corrected signal.

Abstract: Techniques are described for implementing multiband digital predistortion in a broadband transmitter in a manner that provides effective compensation of non-linear distortion arising from integration of a high-power amplifier (HPA). Embodiments segment the signal spectrum of a transmit signal into multiple sub-band signals and apply non-linear distortion compensation separately and concurrently for each sub-band signal. The resulting multi-band digital predistortion (mDPD) compensates both for in-band distortion and for distortions from non-linear interactions between the frequency sub-bands. The disclosed mDPD can provide enhanced performance features, such as handling of memory effects, reduced sampling rate requirements for DPD components, and minimizing detrimental spectral regrowth at the HPA output.

Abstract: A digital phase shifter of the present invention is a digital phase shifter in which digital phase shift circuits are cascade-connected, each of the digital phase shift circuits including a signal line, a pair of inner lines provided on both sides of the signal line, a pair of outer lines provided on outer sides of the inner lines, a first ground conductor connected to one ends of the inner lines and one ends of the outer lines, a second ground conductor connected to the other ends of the outer lines, and a pair of electronic switches provided between the other ends of the inner lines and the second ground conductor. The digital phase shift circuits include a multi-row structure constituted by a front row and a rear row, the front row and the rear row are adjacent to each other, and the ground pattern is connected to the front row at one point.

Abstract: A predistortion circuit for a wireless transmitter includes a signal input configured to receive a baseband signal. Further, the predistortion circuit includes a predistorter configured to generate a predistorted baseband signal using the baseband signal and a select of one of a first predistorter configuration and a second predistorter configuration.

Abstract: A parameter changing device according to the present disclosure includes: a multiplier multiplying a test signal by a back-off rate; a first distortion compensation simulation unit performing distortion compensation processing on a signal acquired by the multiplication, by using a stored parameter; a scaling unit scaling an output signal of the first distortion compensation simulation unit; a second distortion compensation simulation unit performing distortion compensation processing on the test signal, by using a parameter different from the first distortion compensation simulation unit; a differential unit calculating an error between a value of a signal acquired by the scaling and a value of an output signal of the second distortion compensation simulation unit; an approximation error minimization unit calculating a parameter of the second distortion compensation simulation unit minimizing the error; and an output unit outputting a parameter of the second distortion compensation simulation unit to a distor

Abstract: A base station for a wireless communication network is provided. The wireless communication network includes a plurality of base stations, each base station to serve one or more users. One or more users are served by a plurality of base stations to receive a first data signal from the base station and a second data signal from at least one further base station using multi-user superposition transmission, MUST. The base station includes a backhaul interface for a communication with one or more of the plurality of base stations of the wireless communication network. For transmitting the first data signal to one or more users served by the base station and by the further base station, the base station is configured to negotiate a MUST setting with the further base station via the backhaul interface, and map data of the first data signal using a first transmit constellation set according to the negotiated MUST setting.

Abstract: A drive circuit with predistortion. In some embodiments, a system includes a signal input, a predistortion circuit, and an amplifier circuit. The predistortion circuit may be operatively coupled to the signal input and to the amplifier circuit and configured to modify a radio frequency (RF) signal received at the signal input to cause the amplifier circuit to drive, into a load connected to the amplifier circuit, a current that is substantially a replica of the input signal.

Abstract: Power amplifier modules with controllable envelope tracking noise filters are provided herein. In certain embodiments, an envelope tracking system includes a power amplifier module and an envelope tracker that provides the power amplifier module with a power amplifier supply voltage that changes based on an envelope of a radio frequency (RF) signal amplified by the power amplifier module. The power amplifier module includes a controllable filter that filters the power amplifier supply voltage to provide flexibility in filtering envelope tracking noise.

Abstract: Systems and techniques are described that are directed to filter frequency response shift compensation, including compensating for shifting in the rejection band of the filter. Compensation for the shifting in the rejection band can include applying a pre-distortion to attenuate edge resource units (RUs), and applying PHY Protocol Data Unit (PPDU) scheduling schemes. For example, a PPDU scheduling scheme reduce bandwidth in the channel, thereby dropping the out of band RUs. Front ends provide feedback to a respective radio, which allows that radio to apply the appropriate pre-distortion. The front ends can include one or more filters enabling frequency domain coexistence between collocated radios operating in the differing Wi-Fi bands, and a coupler that provides the feedback indicating the frequency response shift to a radio. The radio can then apply a digital pre-distortion to compensate for the shifting in the rejection band.

Abstract: A baseband chip may include a transmitter configured to transmit a first signal. The baseband chip may also include a receiver configured to receive a second signal that includes a receive signal portion and a harmonic interference portion leaked from the transmitter. The baseband chip may further include a harmonic model block configured to multiply a first output from a first harmonic model associated with an amplitude modulation phase modulation (AMPM) look-up table (LUT) and a second output of a second harmonic model associated with an AMAM LUT to generate a third output. The harmonic model block may be further configured to estimate the harmonic interference portion based at least in part on the third output. The baseband chip may also include an interference cancellation block configured to cancel the harmonic interference portion from the second signal to obtain the receive signal portion.

Abstract: A signal transmission apparatus (1) includes: a distortion compensation unit (11) for performing a distortion compensation processing on an input signal (x) by using a Neural Network (112) including L+1 arithmetic layers that include L (L is a variable number representing an integer equal to or larger than 1) hidden layer (112M) and an output layer (112O); a storage unit (13) for storing parameter sets (131) each of which includes a parameter for Q (Q is a variable number representing an integer equal to or smaller than L) arithmetic layer of the L+1 arithmetic layers; and an application unit (142) for selecting one parameter set from the parameter sets based on a signal pattern of the input signal and applying the parameter included in the selected one parameter set to the M number of arithmetic layer, a parameter of another arithmetic layer of the L+1 arithmetic layers, which is other than the Q arithmetic layer, is fixed.

Abstract: The present disclosure relates to a radio frequency power amplifier system (200) comprising a first (114) and a second input port (121). The radio frequency power amplifier system (200) comprises a main amplifier (101) having an input (107) and an output (108) and a first (102) and a second auxiliary amplifier (122) having respective inputs (109, 129) and outputs (110, 128). The radio frequency power amplifier system (200) comprises an internal load (103) connected to the output (110) of the first auxiliary amplifier (102), a feedback network (104) having an input end (111) connected to the output (110) of the first auxiliary amplifier (102) and an output end (112) connected to the input (109) of the first auxiliary amplifier (102). The radio frequency power amplifier system (200) also comprises a feedforward amplifier (123) having an input (124) and an output (130).

Abstract: A controller is a controller for an adjuster that adjusts an input signal for pre-distortion of an amplifier. The controller includes a determination unit that determines a target section corresponding to electric power of the input signal among set sections and a generator that generates a control signal. The adjuster is configured to adjust at least one of an amplitude and a phase of the input signal. An amount of adjustment of at least one of the amplitude and the phase of the input signal is brought in correspondence with each of the sections. The generator generates a signal indicating the amount of adjustment brought in correspondence with the target section as the control signal and provides the control signal to the adjuster.

Abstract: A method of operating an amplifier circuit having a transformer arranged so as to establish a magnetically coupled feedback loop between and output of an amplifier and an input of the amplifier. The method includes providing a DC bias current to the amplifier, and further includes increasing the DC bias current to improve a linearity of the amplifier circuit wherein a transfer gain of the amplifier circuit remains constant when the DC bias current is increased. A loop gain of the magnetically coupled feedback loop is set by selecting a coupling factor and turn-ratio of the transformer.

Abstract: Systems, devices, and methods related to hybrid basis function, neural network-based digital predistortion (DPD) are provided. An example apparatus for a radio frequency (RF) transceiver includes a digital predistortion (DPD) actuator to receive an input signal associated with a nonlinear component of the RF transceiver and output a predistorted signal. The DPD actuator includes a basis-function-based actuator to perform a first DPD operation using a set of basis functions associated with a first nonlinear characteristic of the nonlinear component. The DPD actuator further includes a neural network-based actuator to perform a second DPD operation using a first neural network associated with a second nonlinear characteristic of the nonlinear component. The predistorted signal is based on a first output signal of the basis-function-based actuator and a second output signal of the neural network-based actuator.

Abstract: Certain aspects of the present disclosure provide techniques for digital pre-distortion (DPD). An apparatus for wireless communication generally includes a power amplifier (PA); a first DPD circuit, a second DPD circuit, and a transmitter. The first DPD circuit is generally configured to: obtain an input signal; apply a first DPD to the input signal to generate a first resulting signal; and output the first resulting signal to the second DPD circuit. The second DPD circuit is generally configured to: obtain the first resulting signal from the first DPD circuit; apply a second DPD to the first resulting signal to generate a second resulting signal; and output the second resulting signal to the PA. The PA is generally configured to amplify the second resulting signal to generate an amplified second resulting signal. The transmitter is generally configured to transmit the amplified second resulting signal to a second apparatus.

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 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 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 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.