Statistical spectral output of power law nonlinearity

One of the objectives of analyzing a system is to determine if there are periodic oscillations and, if so, what their amplitude and frequency will be; another objective is to determine the magnitudes of output errors and output powers, when the statistical character of the input signal and noises are known. Methods are given for calculating the output power and the error power for nonlinearities describ-able by power series for Gaussian and for certain other special kinds of input signals.