Cross-terms free forms of some quadratic and higher order time-frequency representations

The S-method based time-frequency analysis is presented. In the case of multicomponent signals, it can produce a sum of the pseudo Wigner distributions of each signal component separately. The only condition is that the spectrogram is cross-terms free. The realization is based on the short-time Fourier transform, for which well studied software methods and hardware systems exist, what makes this method attractive for applications and implementations in time-frequency analysis, including higher-order distributions.