Time-varying third-order cumulant spectra and its application to the analysis and diagnosis of phonocardiogram

Time-varying third-order cumulant spectra for analyzing phonocardiographic signals has been proposed as an effective tool to detect and quantity the temporal quadratic nonlinear interactions. The cumulant-based Wigner bispectra (CWB) are applied to investigate the nonstationarity and non-Gaussianity of both actual normal and clinical phonocardiograms. Significant time-varying bispectral structure is found and discussed. It is expected to use the Wigner bispectra in the understanding of the heart sound mechanism and the improvement of the assistant diagnosis of some heart diseases.