Estimation of the modulation frequency and modulation depth of the fundamental frequency owing to vocal micro-tremor of the voice source signal

摘要

The aim of the article is to present a method for estimating the modulation frequency and modulation level owing to micro-tremor of the vocal fundamental frequency. Vocal micro-tremor designates the modulation of the fundamental frequency of the voice source signal owing to physiological tremor of normal speakers. The analysis is based on the spectral density function of the time series of the glottal cycle lengths. In the spectrum the modulation owing to micro-tremor gives rise to prominent spectral peaks which are positioned at the modulation frequencies. We discuss the results obtained for 38 normal male and female speakers and compare the modulation levels and frequencies to those obtained by others by means of a demodulation of the speech signal.