Patent ID: 7683713

Claim:
A predistorter for correcting distortion caused by a memory effect in amplifying a signal by an amplifier, comprising: level detection means for detecting a level of the signal; amplitude coefficient output means for outputting a coefficient relating to an amplitude corresponding to the detected level; amplitude coefficient delay means for delaying the coefficient relating to the output amplitude; amplitude coefficient difference detection means for detecting the difference between the output coefficient relating to the amplitude and the delayed coefficient relating to the amplitude; amplitude variation means for varying the amplitude of the signal in accordance with the detected difference of the coefficients relating to the amplitude; phase coefficient output means for outputting a coefficient relating to a phase corresponding to the detected level; phase coefficient delay means for delaying the output coefficient relating to the phase; phase coefficient difference detection means for detecting the difference between the output coefficient relating to the phase and the delayed coefficient relating to the phase; phase variation means for varying the phase of the signal in accordance with the detected difference of the coefficients relating to the phase, wherein the signal having the varied amplitude and the varied phase is output to the amplifier.