Control scheme for distortion reduction

摘要

In predistorter (100), non-linear element (126) generates a distortion signal which is injected into the input (110) of a non-linear power amplifier (112 at 118). The distortion signal is optimised by a vector modulator to cancel distortion caused by amplifier (112). The control signals for the vector modulator are provided by a digital signal processor (FIG. 2). The input signal (110) and the output signal (114) are sampled and processed to produce an audio frequency error signal which is correlated in the DSP to produce the control signals for the vector modulator whilst avoiding analogue correlation problems.