ADAPTIVE PREDISTORTER

PROBLEM TO BE SOLVED: To provide an adaptive predistorter capable of controlling a delay, an amplitude and a phase in an equalizer when executing a waveform comparison method.SOLUTION: The adaptive predistorter compensates nonlinear distortion generated in an amplifier 5. Equalization means 17 equalizes linear distortion included in signals (feedback signals) output from the amplifier 5 using an equalization coefficient, nonlinear distortion detection means 24 detects the nonlinear distortion by comparing signals (feed-forward signals) from an input side with signals of an equalization result, and equalization coefficient updating means 22 updates the equalization coefficient so as to equalize the linear distortion included in the signals (feedback signals) of an equalization object with the feed-forward signals as reference signals in the training of the equalization coefficient.