Abstract: A distortion compensation device includes: a distortion compensator configured to output, to a power amplifier, a predistortion signal obtained by performing distortion compensation processing on a transmission signal by using a distortion compensation coefficient, wherein the distortion compensator limits bands of a reference signal and a feedback signal so that the bands fall in a pass band and updates the distortion compensation coefficient based on an error between the reference signal and the feedback signal, the reference signal corresponding to the predistortion signal, the feedback signal corresponding to an output feedback of the power amplifier.

Abstract: A LINC power amplifier selects, based on an amplitude of an input signal, partial signals used for combination, and determines, based on the amplitude and a phase of the input signal, an amplitude and a phase of the selected partial signals so that a range of output power that the LINC power amplifier operates a given efficiency is expanded, inputs the selected partial signals to corresponding power amplifiers, and combines signals obtained by amplification of the selected partial signals by the corresponding power amplifiers.

Abstract: A predistortion apparatus, includes a reducer to output a signal that a peak to average power ratio of an input signal is reduced by clipping, a first predistorter to generate and output a first predistortion signal from the output signal of the reducer, based on a signal obtained by removing a clipping noise caused by the clipping from the output signal of the reducer, so as to reduce energy of a residual error component obtained by removing a clipping noise caused by the clipping from an error signal included in an output of the power amplifier, a second predistorter to generate and output, by using the clipping noise, a second predistortion signal to remove a clipping noise component from the first predistortion signal, and a combiner to generate an input signal of the power amplifier obtained by combining the first predistortion signal and the second predistortion signal.

Abstract: The LINC modulator includes: a separator that generates a plurality of constant envelope signals from a source signal; a plurality of arms through which the plurality of the constant envelope signals are passed, wherein each arm includes a filter that compares frequencies of components of the constant envelope signals with a threshold frequency to generate a first signal including a first frequency part of the source signal, the first frequency part being composed of frequencies lower than a predetermined frequency; a processor that generates a second signal including a second frequency part of the source signal whose frequencies are different from the first frequency part and performs a frequency signal distortion of the second signal to generate a distorted signal; and a quadrature modulator that multiplies the first and distorted signals to reconstruct the constant envelope signals.

Abstract: A linear amplification with nonlinear components (LINC) modulator is provided. The LINC modulator includes: a separator that generates a plurality of constant envelope signals from a source signal; a processor that receives an input signal and detects and removes a phase jump in phase trajectory of the input signal to generate a first signal having a continuous phase trajectory and a second signal having a discontinuous phase trajectory; and a quadrature modulator that mixes the first signal with the second signal to reconstruct the input signal.