US Patent 7190222 Predistorter

A predistortion distortion signal generating unit uses a signal to be amplified to generate a predistortion distortion signal including odd-order signal components of the signal. A delay time difference adjusting unit adjusts a delay time difference between a signal to be amplified and a distortion signal for predistortion such that an influence by the memory effect occurring in the amplifier can be reduced. A predistortion distortion signal giving unit gives a predistortion distortion signal to a signal to be amplified in a form that the delay time difference is adjusted.