Application of cumulant TVHOS to the analysis of composite FM signals in multiplicative and additive noise

Abstract

The paper addresses two questions of time-varying higher-order spectra (TVHOS), whose solutions are essential for the further development of these methods and their applicability to a wide range of situations. They are: (1) defining cumulant TVHOS and (2) predicting the behavior of TVHOS of composite signals. It is shown first that the cumulant Wigner-Ville trispectrum (as a particular member of cumulant TVHOS), can preserve the essential properties of cumulant higher-order spectra (e.g., eliminates Gaussian additive noise) and at the same time is able to characterize the time-variations of the signal's spectral (i.e., trispectral) content. Secondly, when dealing with composite FM signals, a special kind of `non-oscillating cross-terms' appear in the moment TVHOS time-frequency subspace. These cross-terms cannot be eliminated by smoothing the WVT, but rather by appropriate slicing of the full time-multi-frequency space.