The present disclosure provides an amplitude offset calibration method. The method includes: obtaining at least two test feedback signals, where the test feedback signals are analog signals obtained by a transmitter in a test mode according to a test signal, at least two test signals in one-to-one correspondence to the at least two test feedback signals are digital signals pre-generated by the transmitter, and amplitudes of the at least two test signals are different; obtaining at least two corresponding baseband signals according to the at least two test feedback signals, where the baseband signals are a digital signal, and the baseband signals are in one-to-one correspondence to the test feedback signals; and determining an amplitude offset value according to the at least two test signals and the at least two baseband signals.

Reducing harmonics in a radio transmitter can involve using an electronically tunable harmonic filter (ETHF) in a transmit path at the output of an RF power amplifier stage to reduce harmonic signal components in the RF transmit signal. At least one filter characteristic of the ETHF is selectively controlled using one or more RF switch. The one or more RF switches that are used to control the ETHF can include a CMOS-SOI and/or a MEMs type of switch. Various filter characteristics of the ETHF can be controlled including a bandwidth and/or a center frequency of the ETHF.

Methods and devices are disclosed for amplifying radio signals between a terminal and an antenna or an antenna connection of a circuit having an amplification unit and a detector unit, which has signal branches designed for different frequency ranges, and a power detector. A transmission signal received by the terminal is divided into at least a first signal part and a second signal part. The first signal part is applied to the signal branches of the detector unit. A frequency range of the first signal part is determined by sequential application of the signal branches of the detector unit to the power detector for evaluating a power of the first signal part. For the second signal part, the signal routing in the amplification unit is adjusted based on the frequency range determined by the detector unit. At least the second signal part is amplified by the amplification unit.

Methods, systems, and devices for wireless communications are described. For example, a transmitting wireless device, such as a user equipment or a base station, may apply a first set of digital pre-distortion (DPD) coefficients to a plurality of antenna elements to form a first transmit beam. The wireless device may determine to switch from using the first transmit beam to using a second transmit beam that is different from the first transmit beam and may apply a second set of DPD coefficients to the plurality of antenna elements to form the second transmit beam, where the second set of DPD coefficients is different from the first set of DPD coefficients. The wireless device may transmit signaling using the second transmit beam based at least in part on applying the second set of DPD coefficients.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit, to a base station, a capability message indicating a capability supporting network-side phase noise compensation. The UE may transmit, to the base station, phase tracking reference signals based on transmitting the capability message. In an example, the phase tracking reference signals may include a UE phase noise component which may be associated with a local oscillator of the UE. The UE may receive, from the base station, a compensated downlink transmission that is compensated based on the UE phase noise component. In generating the compensated downlink transmission, the base station may apply a multiplication factor associated with the estimated UE phase noise component to the compensated downlink transmission.

A transceiver is configured for a calibration mode of operation in which an impedance of a transmit chain is tuned responsive to a power measurement of a mixed RF calibration signal to form a tuned transmit chain. A direct conversion mixes an RF calibration signal with a DC offset signal to form the mixed calibration signal. During a normal mode of operation, a heterodyne mixer mixes an LO signal with an IF signal to produce an RF signal that is amplified through the tuned transmit chain.

A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM) may include sending a signal through an up-converter of a transmit path to provide an up-converted signal, determining the up-converted signal, determining one or more IQMM parameters for the transmit path based on the determined up-converted signal, and determining one or more pre-compensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path. In some embodiments, the up-converted signal may be determined through a receive feedback path. In some embodiments, the up-converted signal may be determined through an envelope detector.

Systems and methods for linearizing a radio system are disclosed. In some embodiments, a radio system comprises an antenna array, transmit branches comprising respective power amplifiers, a predistortion subsystem comprising predistorters for the transmit branches respectively, a receive antenna element, a transmit observation receiver having an input coupled to the receive antenna element, and an adaptor. The predistorters predistort respective transmit signals to provide predistorted transmit signals to the respective transmit branches for transmission via respective active antenna elements in the antenna array. The transmit observation receiver is operable to receive, via the receive antenna element, a combined receive signal due to coupling between the receive antenna element and the active antenna elements. The adaptor is operable to generate a combined reference signal based on the transmit signals and configure predistortion parameters input to the predistorters based on the combined reference signal and the combined receive signal.

An analog pre-distortion processing circuit and a signal processing device, the analog pre-distortion processing circuit comprises a narrowband spread spectrum module, an analog pre-distortion module and a filtering module. The narrowband spread spectrum module is used for spreading an input narrowband radio frequency signal into a broadband radio frequency signal. The bandwidth of the broadband radio frequency signal is a preset bandwidth. The analog pre-distortion module is used for carrying out analog pre-distortion linearization processing on the broadband radio frequency signal to obtain a linearized broadband radio frequency signal; the preset bandwidth is located in the optimal cancellation bandwidth of the analog pre-distortion module. The filtering module is used for carrying out signal filtering on the linearized broadband radio frequency signal to obtain a linearized narrowband radio frequency signal.

Provided is a distortion compensation device performing distortion compensation on a signal to be amplified by an amplifier, of which an internal state affecting a distortion characteristic varies, using a distortion compensation model, wherein the distortion compensation model includes a plurality of calculation models having respective distortion compensation characteristic for the amplifier in different internal states, and a combiner combining the plurality of calculation models at a combination ratio corresponding to the internal state that varies.