Effect of Envelope Detectors and Filters on a Digitally Controlled RF Predistortion System

This paper discusses the effect of different envelope detection methods and anti-aliasing filters on the linearisation ability of a RF predistortion system based on phase and amplitude modulator. Three common envelope detection methods used in RF predistortion systems, namely power detector, logarithmic amplifier and a diode detector are studied. Also the effect of power amplifier nonlinearity on the selection of detector and filters is discussed. Theoretical calculations and simulation results of the effect of detectors and filtering are presented