Abstract: A transmitter includes a signal generator arranged to generate a digital baseband signal representative of a signal for transmission; a digital predistortion, DPD, circuit configured to predistort the digital baseband signal; and a power amplifier is arranged to amplify the predistorted signal. The DPD circuit includes a first signal shaping circuit operably coupled to the signal generator and the DPD predistortion circuit and configured to receive the generated digital signal and apply first envelope shaping to shape the predistortion applied to at least the amplitude of the generated digital signal and produce a first DPD signal; a second signal shaping circuit operably coupled to the signal generator and an output of the DPD predistortion circuit and configured to receive and apply the second envelope shaped digital signal to the first DPD signal and produce a second envelope shaped DPD signal.

Abstract: A transmitter includes a signal generator arranged to generate a digital baseband signal representative of a signal for transmission; a digital predistortion, DPD, circuit configured to predistort the digital baseband signal; and a signal adjustment circuit operably coupled to the signal generator and the DPD circuit and configured to receive the generated signal and apply shaping to adjust the predistortion applied to the envelope of the generated signal.

Abstract: A transmitter includes a signal generator arranged to generate a digital baseband signal representative of a signal for transmission; a digital predistortion, DPD, circuit configured to predistort the digital baseband signal; and a signal adjustment circuit operably coupled to the signal generator and the DPD circuit and configured to receive the generated signal and apply shaping to adjust the predistortion applied to the envelope of the generated signal.

Abstract: A transmitter includes a signal generator arranged to generate a digital baseband signal representative of a signal for transmission; a digital predistortion, DPD, circuit configured to predistort the digital baseband signal; and a power amplifier is arranged to amplify the predistorted signal. The DPD circuit includes a first signal shaping circuit operably coupled to the signal generator and the DPD predistortion circuit and configured to receive the generated digital signal and apply first envelope shaping to shape the predistortion applied to at least the amplitude of the generated digital signal and produce a first DPD signal; a second signal shaping circuit operably coupled to the signal generator and an output of the DPD predistortion circuit and configured to receive and apply the second envelope shaped digital signal to the first DPD signal and produce a second envelope shaped DPD signal.

Abstract: One communication system includes a first die, a second die and a front-end circuit. The first die has an up-converter and a digital baseband (DBB) processing circuit. The second die has a down-converter. The front-end circuit couples an antenna to the first and second dies. Another exemplary communication system includes a first die, a second die and a front-end circuit. The first die performs digital baseband (DBB) processing, and generates a first signal with a higher frequency according to a second signal, wherein the second signal is derived from an output signal of the DBB processing. The second die generates a third signal with a lower frequency according to a fourth signal. The front-end circuit couples the first signal from the first die to an antenna and couples the fourth signal from the antenna to the second die.

Abstract: A radio frequency (RF) receiver includes a digital tuning engine; and I-path and Q-path analog filters, tuned by the digital tuning engine. The digital tuning engine gets an I/Q imbalance difference, and the digital tuning engines tunes the I-path analog filter and/or the Q-path analog filter based on the I/O imbalance difference.

Abstract: A radio frequency (RF) transmitter includes a power amplifier comprising a plurality of power amplifier cells. At least one digital signal processing module of the RF transmitter is operably coupled to the power amplifier and comprises at least one digital pre-distortion component arranged to apply at least one digital pre-distortion codeword to the plurality of power amplifier cells, wherein the at least one digital pre-distortion codeword is applied to at least one of the plurality of power amplifier cells via a digital filter. A combiner is arranged to combine outputs of the plurality of power amplifier cells thereby generating an analogue RF signal for transmission over an RF interface based at least partly on the digitally filtered at least one digital pre-distortion codeword.

Abstract: A communication unit comprises a decimator configured to sample a variable control signal and output a reduced bandwidth variable control signal; and a multi-level power supply, MLPS, comprising an input and an output, wherein the input is coupled to the decimator and configured to receive the reduced bandwidth variable control signal and, in response thereto, the output delivers multi-level output voltages to supply a power amplifier, PA, module.

Abstract: A method of calibrating an envelope tracking system for a supply voltage for a power amplifier module within a radio frequency (RF) transmitter of a wireless communication unit is described. The method comprising, within at least one signal processing module of the wireless communication unit, applying a training signal comprising an envelope that varies with time to an input of the RF transmitter, receiving at least an indication of instantaneous output signal values for the power amplifier module in response to the training signal, calculating instantaneous gain values based at least partly on the received output power values, and adjusting a mapping function between an instantaneous envelope of a waveform signal to be amplified by the power amplifier module and the power amplifier module supply voltage to achieve a power amplifier module gain, for example that is monotonically increasing as a function of power amplifier output power.

Abstract: An impedance tuning control apparatus has a processing circuit and an output circuit. The processing circuit determines a first control setting according to a first performance metric, and performs a search operation with a search start point set by the first control setting to find a second control setting according to a second performance metric. The second performance metric is different from the first performance metric. The output circuit outputs a final control setting to a tuner, wherein the final control setting is derived from the second control setting.

Abstract: A radio frequency (RF) transmitter has at least one digital signal processing module and at least one power amplifier module. The digital signal processing module includes at least one digital pre-distortion component arranged to receive at least one complex input signal, perform two-dimensional non-uniform mapping of the complex input signal to a first, in-phase, digital pre-distortion control word and a further, quadrature, digital pre-distortion control word, and output the in-phase and quadrature pre-distortion digital control words. The power amplifier module includes a first, in-phase, array of switch-mode power cells and at least one further, quadrature, array of switch-mode power cells. The two-dimensional non-uniform mapping has a pre-distortion profile at least partly based on an input/output relationship for the power amplifier module arranged to generate an analog RF signal based at least partly on the in-phase and quadrature digital pre-distortion control words.

Abstract: A radio frequency transmitter includes a digital power amplifier and a bias control circuit. The digital power amplifier is arranged for receiving at least a radio frequency input signal, a digital amplitude control word signal and at least one bias voltage to generate a radio frequency output signal. The bias control circuit is coupled to the digital power amplifier, and is arranged for adjusting the at least one bias voltage according to a power control signal.

Abstract: A communication unit comprises a decimator configured to sample a variable control signal and output a reduced bandwidth variable control signal; and a multi-level power supply, MLPS, comprising an input and an output, wherein the input is coupled to the decimator and configured to receive the reduced bandwidth variable control signal and, in response thereto, the output delivers multi-level output voltages to supply a power amplifier, PA, module.

Abstract: A communication unit comprises a radio frequency, RF, transmitter comprising: a power amplifier, PA, module; an envelope tracking system operably coupled to the PA module and arranged to variably control a supply voltage for the PA module; and a load control system operably coupled to an output of the PA module and arranged to control a power amplifier output load.

Abstract: A method suppresses transmission noise comprised in a plurality of downlink signals received by one of a first radio module or a second radio module comprised in a communications apparatus. The method receives a plurality of first signals and a plurality of second signals, wherein the first signals and the second signals are the downlink signals respectively received via different antennas of the one of the first radio module or the second radio module, or the first signals are the downlink signals received by the one of the first radio module or the second radio module and the second signals are a portion of the uplink signals provided by the other one of the first radio module and the second radio module, and processes the plurality of first signals and the plurality of second signals to cancel transmission noise comprised in the plurality of downlink signals.

Abstract: A radio frequency (RF) transmitter including at least one digital signal processing module is described. The at least one digital signal processing module is arranged to receive a complex digital input signal, successively apply pre-distortion to the received complex digital input signal with a progressively finer granularity, simultaneously progressively increase a sampling rate of the received complex digital input signal, and output a first, in-phase digital control word and a second, quadrature, digital control word for controlling at least one digital power amplifier component to generate an RF signal representative of the received complex digital input signal.

Abstract: An impedance tuning control apparatus has a processing circuit and an output circuit. The processing circuit determines a first control setting according to a first performance metric, and performs a search operation with a search start point set by the first control setting to find a second control setting according to a second performance metric. The second performance metric is different from the first performance metric. The output circuit outputs a final control setting to a tuner, wherein the final control setting is derived from the second control setting.

Abstract: A wireless transmitter has a digital baseband module and a radio-frequency (RF) transmitter. The digital baseband module generates a multi-mode modulated signal by using a plurality of digital synthesizers. The RF transmitter has a frequency synthesizer and a digital power amplifier (DPA). The frequency synthesizer generates an oscillation signal with an RF carrier frequency. The DPA generates a multi-standard RF signal according to the multi-mode modulated signal and the oscillation signal.

Abstract: A method suppresses transmission noise comprised in a plurality of downlink signals received by one of a first radio module or a second radio module comprised in a communications apparatus. The method receives a plurality of first signals and a plurality of second signals, wherein the first signals and the second signals are the downlink signals respectively received via different antennas of the one of the first radio module or the second radio module, or the first signals are the downlink signals received by the one of the first radio module or the second radio module and the second signals are a portion of the uplink signals provided by the other one of the first radio module and the second radio module, and processes the plurality of first signals and the plurality of second signals to cancel transmission noise comprised in the plurality of downlink signals.

Abstract: A radio frequency (RF) receiver includes a digital tuning engine; and I-path and Q-path analog filters, tuned by the digital tuning engine. The digital tuning engine gets an I/Q imbalance difference, and the digital tuning engines tunes the I-path analog filter and/or the Q-path analog filter based on the I/Q imbalance difference.