Patent ID: 8014443

Claim:
A non-linear distortion detection method in a distortion compensation amplifying device including: an amplifier which subjects an input signal to power amplification; distortion compensation means for compensating non-linear distortions which appear in the amplifier, as to an inputted modulation signal to be amplified; a distortion detection unit which detects distortion components contained in an output of the amplifier and estimates the distortions, on the basis of a feedback signal of the amplifier output; and a control unit which controls the distortion compensation means on the basis of the estimation of the distortions in the distortion detection unit; wherein: the distortion detection unit equalizes the feedback signal of the amplifier output with a reference symbol being an input signal to the distortion compensation means, it calculates an equalization error between the equalized signal and the reference symbol, and it estimates the distortions on the basis of the equalization error; and the distortion detection unit changes an amplitude of the input signal to the distortion compensation means, cyclically from a low level to a high level, it detects equalization errors at the respective levels of the amplitude of the input signal and averages the detected equalization errors, and it estimates distortions at the respective amplitude levels on the basis of results of the averaging.