Modeling correlated and uncorrelated distortion in communication systems

Simulation technology suitable for extracting correlated and uncorrelated distortion in communication systems is presented. This is achieved through a new frequency- indexing scheme with the arithmetic operator method that separately tracks correlated and uncorrelated intermodulation products when multi-tone signals with uncorrelated phase are amplified through a nonlinear system. The indexing scheme is illustrated with a three-tone example and results from a fifth-order nonlinear amplifier excited by fifteen independent tones are considered. In the example it is shown that undesirable uncorrelated in-band distortion is lower than the innocuous correlated in-band distortion.