Representation and measurement of nonlinearities in stimulus signals

In this paper, we will present a simple and cost effective, yet accurate, setup for measuring the amplitude distribution of a signal and its probability density function. From this, it will be shown how to measure linear and nonlinear errors through a third-order Taylor series representation of the distorted signal. We will also show how this representation may be used to subtract the nonlinearity of the stimulus signal from a histogram characterization and how it could be employed as a horizontal metric for adequacy of the amplitude distribution, also in the histogram method. Finally, experimental results concerning the characterization of two sine wave generators will be presented and compared with measurements made with a spectrum analyzer.