Random Signal Method of Nonlinear Amplitude Distortion Measurement

The degree and orders of nonlinearity of a system can be determined by the use of a random test signal. A Gaussian-distributed random signal with a uniform power spectral density except for a narrow spectral notch is used as an input test signal. The power within the notch at the system output is a measure of the degree of system nonlinearity. Relative variations of the output power within the notch with input loading identify the orders of nonlinearity.