Harmonic spectrogram for the analysis of semi-periodic physiologic signals

This paper describes a simple method that improves the resolution of power spectral density (PSD) estimates of nonsinusoidal semi-periodic signals. This method can also be used to generate time-frequency mappings similar to the spectrogram. This is a useful tool for the analysis of physiologic signals such as the electrocardiogram and blood pressure. Several examples are given of the method applied to biomedical signals.