Patent ID: 7414470

Claim:
A predistortion amplifier for compensating distortion, comprising: an amplifying unit; a power detection unit for detecting an electric power or amplitude of an input signal to output an input level; a distortion compensation table for storing compensation values corresponding to the input level, the compensation values being used for compensating nonlinear characteristics of the amplifying unit; a control unit for updating the compensation values so that signal components outside of a desired frequency range that are included in an output signal of the amplifying unit do not exceed a preset level; a predistortion unit for generating a predistorted signal to be inputted to the amplifying device by performing a predistortion on the amplitude and a phase of the input signal, the predistortion being performed by using the compensation values corresponding to the input level outputted from the power detection unit stored in the distortion compensation table; and an offset adder for adding an offset value to an amplitude compensating value, the amplitude compensating value being assigned to the amplitude of the input signal by the compensation values based on the input level, and the offset value being determined regardless of the input level, wherein the control unit includes an offset generator for calculating an average value of the amplitude compensating value for each input level when the compensation values are updated, thereby generating the offset value by inverting a sign of the average value.