Estimation Of Frequency Response And Intermodulation Distortion From Bispectra

Intermodulation distortion measurements are an important aspect of the design and test of communication systems. This paper provides a method based on the Volterra representation of nonlinear systems to measure the intermodulation distortion due to second order nonlinearities. As we show, this approach enables us to compute the distortion at more frequency points in the frequency plane than does the conventional two-tone test. Two methods, one based on cross-correlation and cross-third moments, and another, based on cross-spectrum and cross-bispectrum, are developed.