Laurence Cnockaert

Fundamental frequency estimation and vocal tremor analysis by means of Morlet wavelet transforms

A vocal frequency estimation method and an analysis of vocal tremor are proposed. Vocal tremor is a narrow-band low-frequency perturbation of the vocal frequency. The vocal frequency estimate is the instantaneous frequency calculated in an automatically selected frequency-band of a wavelet transform of the speech signal. The vocal frequency estimation method is compared to an event-based method and a Hilbert-transform method for speech signals. The tremor frequency and amplitude are obtained by means of a continuous wavelet transform applied to the instantaneous frequency trace. The proposed analysis has been applied to parkinsonian and normophonic speakers. The results suggest that the vocal tremor features differ for both groups.