Abstract: Systems and methods for compensating a transmit signal for charge trapping effects of a power amplifier are provided. In certain embodiments, a non-linear filter is trained based on time aligning a first set of observations taken from digital transmit data prior to conversion to a radio frequency transmit signal, and a second set of observations taken from an output of a power amplifier that amplifies the radio frequency transmit signal. In certain implementations, the first set of observations and the second set of observations are obtained without decimation. Rather, decimation is provided after timing alignment. By implementing the DPD system in this manner, signal data is not lost by decimation and more accurate timing alignment between the sets of observations is achieved.

Abstract: Systems, devices, and methods related to performing digital predistortion in radio frequency (RF) systems are provided. A digital predistortion (DPD) arrangement includes a DPD actuator circuit to predistort, using DPD coefficients, at least a portion of an input signal, the DPD coefficients associated with a characteristic of a nonlinear component. The DPD arrangement further includes a DPD capture circuit to perform, based on a capture cycle timing, multiple captures of a feedback signal, the feedback signal indicative of an output of the nonlinear component; compute, based on one or more characteristics of the multiple captures, one or more criteria for a subsequent capture of the feedback signal; and perform, based on the one or more criteria, the subsequent capture of the feedback signal. The DPD arrangement circuit further includes a DPD adaptation circuit to update the DPD coefficients based at least in part on the subsequent capture.

Abstract: Systems, devices, and methods related to performing digital predistortion in radio frequency (RF) systems are provided. A digital predistortion (DPD) arrangement includes a DPD actuator circuit to predistort, using DPD coefficients, at least a portion of an input signal, the DPD coefficients associated with a characteristic of a nonlinear component. The DPD arrangement further includes a DPD capture circuit to perform, based on a capture cycle timing, multiple captures of a feedback signal, the feedback signal indicative of an output of the nonlinear component; compute, based on one or more characteristics of the multiple captures, one or more criteria for a subsequent capture of the feedback signal; and perform, based on the one or more criteria, the subsequent capture of the feedback signal. The DPD arrangement circuit further includes a DPD adaptation circuit to update the DPD coefficients based at least in part on the subsequent capture.

Abstract: Systems, devices, and methods related to performing digital predistortion in radio frequency (RF) systems are provided. A digital predistortion (DPD) arrangement includes a DPD actuator circuit to predistort, using DPD coefficients, at least a portion of an input signal, the DPD coefficients associated with a characteristic of a nonlinear component. The DPD arrangement further includes a DPD capture circuit to perform, based on a capture cycle timing, multiple captures of a feedback signal, the feedback signal indicative of an output of the nonlinear component; compute, based on one or more characteristics of the multiple captures, one or more criteria for a subsequent capture of the feedback signal; and perform, based on the one or more criteria, the subsequent capture of the feedback signal. The DPD arrangement circuit further includes a DPD adaptation circuit to update the DPD coefficients based at least in part on the subsequent capture.

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: Some embodiments herein describe a radio frequency power semiconductor device that include a first non-linear filter network for compensating for lower frequency noise of a power amplifier. The first non-linear filter network can include a plurality of infinite impulse response filters and corresponding corrective elements to correct for a non-linear portion of the power amplifier. The radio frequency power semiconductor device can further include a second non-linear filter network for compensating for broadband distortion. The second non-linear filter network can be connected in parallel to the first non-linear filter network. The broadband distortion can include digital predistortion and the narrowband distortion can include charge trapping effects. The first non-linear filter network can comprise Laguerre filters. The second non-linear filter network can comprise general memory polynomial filters.

Abstract: In a dynamic signal traffic scenario, a narrowband to wideband transition in a DPD system results in a tilt in the output spectrum until the next DPD adaptation cycle occurs. To address this problem, regularization term is applied with a weighing factor when performing DPD coefficient estimation and adaptation. The regularization term can be obtained from in a variety of ways: using pre-stored waveforms, through factory or in-situ calibration, or through an adaptive or opportunistic update by observing the system. Application of the regularization term improves the spectrum flatness for a narrow to wideband signal transition, and does not require transmitting additional calibration tones to correct the gain flatness.

Abstract: Systems, devices, and methods related to performing digital predistortion in radio frequency (RF) systems are provided. A digital predistortion (DPD) arrangement includes a DPD actuator circuit to predistort, using DPD coefficients, at least a portion of an input signal, the DPD coefficients associated with a characteristic of a nonlinear component. The DPD arrangement further includes a DPD capture circuit to perform, based on a capture cycle timing, multiple captures of a feedback signal, the feedback signal indicative of an output of the nonlinear component; compute, based on one or more characteristics of the multiple captures, one or more criteria for a subsequent capture of the feedback signal; and perform, based on the one or more criteria, the subsequent capture of the feedback signal. The DPD arrangement circuit further includes a DPD adaptation circuit to update the DPD coefficients based at least in part on the subsequent capture.

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: Some embodiments herein describe a radio frequency power semiconductor device that include a first non-linear filter network for compensating for lower frequency noise of a power amplifier. The first non-linear filter network can include a plurality of infinite impulse response filters and corresponding corrective elements to correct for a non-linear portion of the power amplifier. The radio frequency power semiconductor device can further include a second non-linear filter network for compensating for broadband distortion. The second non-linear filter network can be connected in parallel to the first non-linear filter network. The broadband distortion can include digital predistortion and the narrowband distortion can include charge trapping effects. The first non-linear filter network can comprise Laguerre filters. The second non-linear filter network can comprise general memory polynomial filters.

Abstract: A method of generating parameters for a predistortion circuit in an integrated circuit using a matrix is disclosed. The method comprises storing a first column of a first matrix; generating the remaining columns of the first matrix based upon the first column of the matrix; generating a plurality of rows of a second matrix by performing a first set of calculations; and generating the remaining rows of the second matrix by selectively shifting the first rows of the second matrix.

Abstract: A circuit for receiving a sample of an input signal to be used to calculate parameters for a predistortion circuit in an integrated circuit is described. The circuit comprises a power measurement circuit coupled to receive the input signal; a first port of a dual port random access memory for receiving data associated with power of the input signal over a predetermined period of time; and a second port of a dual port random access memory for generating the data associated with the power of the input signal stored over the predetermined period of time. A method of receiving a sample of an input signal to be used to calculate parameters for a predistortion circuit in an integrated circuit is also described.

Abstract: A method of accepting a sample of an input signal to be used to calculate parameters for a predistortion circuit in an integrated circuit is disclosed. The method comprises accumulating data associated with an input signal over a period of time; detecting the sample of the input signal at a predetermined time; comparing the sample of the input signal to the accumulated data; and determining whether the sample of the input signal is acceptable to be used to calculate parameters for the predistortion circuit. A circuit for accepting a sample of an input signal to be used to calculate parameters for a predistortion circuit in an integrated circuit is also disclosed.

Abstract: An approach for determining corrective predistortion functions includes maintaining a history of recent estimations of a plurality of corrective predistortion functions. Each of those functions corresponds to a respective signal characteristic. By determining a feature of each of those functions from the history, one of the corrective predistortion functions is selected for a next estimation based upon which of the functions has a feature within the history that satisfies a selected criteria. In a disclosed example, the function having the lowest number of estimations within a recent history is selected as the function to have the highest priority for a next estimation.

Abstract: Determining a predistortion function includes sampling a signal to obtain a plurality of capture sets within a single sampling window. Each of the capture sets is analyzed to determine whether it satisfies preselected criteria. Example criteria include desired characteristics of a capture set average power, capture set peak power and a number of peaks within a capture set. If any capture set within the sampling window satisfies all of the preselected criteria and has the highest number of peaks, that capture set will be used for determining a predistortion function. A multiple capture set selection module applies the preselected criteria for selecting an appropriate capture set for determining the predistortion function. The predistortion function is used for applying predistortion to a signal before that signal is processed by a distorting component that introduces distortion so that the predistortion can compensate for or cancel out such distortion.

Abstract: A method of adapting parameters for a predistortion circuit in an integrated circuit is disclosed. The method comprises receiving, at the predistortion circuit, an input signal to be amplified by a power amplifier; determining a value associated with an information tag for the input signal; applying parameters to the predistortion circuit based upon the determined value; receiving an output of the power amplifier at an input of the integrated circuit; comparing an output of the predistortion circuit with the output of the power amplifier; and generating updated parameters to be applied to the predistortion circuit. An integrated circuit having a circuit for adapting parameters for a predistortion circuit of the integrated circuit is also disclosed.

Abstract: A method of generating parameters for a predistortion circuit in an integrated circuit is disclosed. The method comprises receiving, at the predistortion circuit, an input signal to be amplified by a power amplifier; receiving an output of the power amplifier at an input of the integrated circuit; comparing an output of the predistortion circuit with the output of the power amplifier; conforming the output of the power amplifier with the output of the predistortion circuit; and generating parameters to be applied to the predistortion circuit based upon the conformed output of the power amplifier and the predistortion circuit. An integrated circuit having a circuit for generating parameters for a predistortion circuit of the integrated circuit is also disclosed.

Abstract: An integrated circuit having a circuit for reducing distortion in a power amplifier is disclosed. The integrated circuit comprises a predistortion circuit coupled to receive a signal to be amplified; sample capture buffers coupled to an output of the predistortion circuit and an input/output port of the integrated circuit; and an estimator circuit coupled to the sample capture buffers, wherein the estimator circuit generates parameters for the predistortion circuit based upon the output of the predistortion circuit and an output of the power amplifier received at the input/output port of the integrated circuit. A method of reducing distortion in a power amplifier is also disclosed.

Abstract: An integrated circuit having a circuit for reducing distortion in a power amplifier is disclosed. The integrated circuit comprises a predistortion circuit coupled to receive a signal to be amplified; sample capture buffers coupled to an output of the predistortion circuit and an input/output port of the integrated circuit; and an estimator circuit coupled to the sample capture buffers, wherein the estimator circuit generates parameters for the predistortion circuit based upon the output of the predistortion circuit and an output of the power amplifier received at the input/output port of the integrated circuit. A method of reducing distortion in a power amplifier is also disclosed.

Abstract: A corrective predistortion function is applied to a signal to compensate for or cancel out distortion that is introduced by a component that processes the signal. A disclosed example includes applying a corrective predistortion function to a transmitted signal used for wireless communications. A technique for selecting the corrective predistortion function includes determining a current power level of the signal. When the current power level is at or below a lift level between a maximum signal power level and a minimum signal power level, a corrective predistortion function corresponding to the lift level is applied to the signal. When the actual signal power level is above the lift level, a corrective predistortion function corresponding to the actual current power level is applied.