IMPROVED PREDISTORTION COMPENSATION FOR A POWER AMPLIFIER

摘要

The invention relates to an amplifier arrangement (10) for amplifying an inp ut using a distorting main power amplifier (14) such as one operating as a clas s AB amplifier. The method and apparatus add to the input signal to the main amplifier (14) a predistortion signal intended to compensate for the distortion added by the main power amplfier (14). In accordance with the invention, the input to the predistortion circuit (12) is modified by measuring peak-to-peak signal values of the distortion in the output of the main power amplifier (14). The peak-to-peak values are measured in a signal derived by comparing an output derived from the main amplifier (14) with an output derived from the input signal. A digitally controlled processor (16) iteratively modifies various phase and gain controls to adjust the output of the amplifier.