AM-AM and AM-PM distortion characterization of satellite transponders/base station transmitters using spectrum measurements

Abstract

This paper proposes a method for measuring AM-AM and AM-PM distortion of power amplifiers (PAs) of satellite transponders and base station transmitters using power spectrum measurements. It consists of using unequal three-tone signal to drive either the base station power amplifier's transmitter or the satellite transponder's power amplifier and to measure the level of these tones at the output of the transmitter/transponder. By comparison of the spectrum at the input and output of the PA, one can calculate the AM-AM compression factor and the AM-PM conversion coefficient of the power amplifier of the transmitter or transponder using close form expressions.