Abstract:
A communication unit having a transmitter and method of harmonic distortion content reduction is described. The transmitter is configured to operate in a training mode of operation and a normal transmission mode of operation. The transmitter includes a signal generator; a digital predistortion, DPD, circuit; and a first frequency shift circuit to frequency shift a signal for transmission in a first frequency direction. A feedback path and a second frequency shift circuit frequency shifts a fed back power amplified predistorted signal portion in a second frequency direction opposite to the first frequency direction. A calibration engine, receives and compares a digital baseband signal representative of a signal for transmission with the fed back power amplified predistorted signal portion shifted in the second frequency direction to determine at least one DPD compensation value only during a training mode of operation.
Abstract:
An electronic device and a method for calibrating a temperature related scattering matrix (S-matrix) of a temperature sensitive device are provided. The electronic device includes a temperature sensitive device for receiving a forward signal and a reverse signal corresponding to a desired signal and a calibration kit for providing a switchable impedance. During a first phase, the electronic device operates in a first temperature, and multiple first calculation results are calculated according to the forward signal and the reverse signal by setting the switchable impedance to be multiple impedances, respectively. During a second phase, the electronic device operates in a second temperature, and multiple second calculation results are calculated according to the forward signal and the reverse signal by setting the switchable impedance to be the multiple impedances, respectively. In addition, the temperature related S-matrix is calibrated according to the multiple first calculation results and the multiple second calculation results.
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. A multiplier is configured to receive and multiply the digital signal and the second envelope shaped DPD signal and output a digitally predistorted signal for transmission.
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:
Examples of front-end modules, apparatuses and methods for coupling compensation in a closed-loop digital pre-distortion (DPD) system are described. The closed-loop DPD circuit may include a PA and a loopback path. The PA may receive a PA input signal and amplify the PA input signal to provide a PA output signal proportional to a product of the PA input signal and a gain of the PA. The loopback path may receive the PA output signal to output a loopback signal. A forward coupling and a backward coupling may exist between the PA input signal and an output of the loopback path. The output of the loopback path may be proportional to a product of the PA output signal and a gain of the loopback path. The loopback path may include a coupling cancellation mechanism configured to cancel couplings between the PA input signal and the loopback signal.
Abstract:
Examples of front-end modules, apparatuses and methods for coupling compensation in a closed-loop digital pre-distortion (DPD) system are described. The closed-loop DPD circuit may include a PA and a loopback path. The PA may receive a PA input signal and amplify the PA input signal to provide a PA output signal proportional to a product of the PA input signal and a gain of the PA. The loopback path may receive the PA output signal to output a loopback signal. A forward coupling and a backward coupling may exist between the PA input signal and an output of the loopback path. The output of the loopback path may be proportional to a product of the PA output signal and a gain of the loopback path. The loopback path may include a coupling cancellation mechanism configured to cancel couplings between the PA input signal and the loopback signal.
Abstract:
An electronic device and a method for estimating scattering parameters of a two-port network are provided. The electronic device includes a two-port network, a directional coupler, an input calibration kit placed in front of the two-port network, an output calibration kit placed behind the two-port network, and a control switch connected between the directional coupler and the two-port network. The directional coupler transmits a desired signal and receives a forward signal and a reverse signal from the two-port network. When the control switch is turned off, input calculation results are calculated according to the forward signal and the reverse signal by controlling the input calibration kit. When the control switch is turned on, output calculation results are calculated according to the forward signal and the reverse signal by controlling the output calibration kit. The scattering parameters are estimated according to the input calculation results and the output calculation results.
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. A multiplier is configured to receive and multiply the digital signal and the second envelope shaped DPD signal and output a digitally predistorted signal for transmission.
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.