Patent ID: 9438281
Filing Date: 2016-09-06
CPC Classification: H03F,H04B

Claim Text:
1. A distortion compensation apparatus that compensates for distortion of an output signal from a circuit for modulating and amplifying an input signal, the distortion compensation apparatus comprising: a demodulation section that acquires the output signal, and generates a demodulation signal by demodulating the output signal; a delay adjustment section that computes a delay amount of the demodulation signal with respect to the input signal, adjusts a delay of the demodulation signal with respect to the input signal based on the delay amount, and outputs an delay adjusted input signal and a delay adjusted demodulation signal; a distortion compensation section that determines a distortion compensation coefficient in an adaptive digital predistortion process based on the delay adjusted input signal and the delay adjusted demodulation signal; and a multiplication section that multiplies the input signal by the distortion compensation coefficient determined by the distortion compensation section, wherein the distortion compensation section corrects a phase shift caused by phase rotation between the delay adjusted input signal and the delay adjusted demodulation signal, and determines the distortion compensation coefficient based on a phase shifted input signal and a phase shifted demodulation signal in which the phase shift is corrected.