Model and Analysis of Speech Function

Man's speech function is investigated from the standpoint of electronics, physiology and psychology. On the analysis of the physiological results and the earlier electronic model for the auditory system, it is pointed out that a mechanism of lateral inhibition neglected in the electronic model must exist in auditory system(particularly in the basilar membrane), and also that the difference in the function of inner and outer hair cells is important in modeling the speech perception. Basing on this consideration, a new electronic model is proposed for the basilar membrane and inner and outer hair cells. A model for the mechanism of speech production is also constructed by using the analogy with the solid-state physics, and it is shown that the frequency spectrum of speech wave is closely related with the dispersion relation of the medium (vocal tract). Finally, amethod for the pitch normalization of the speech signal and a method of speech perception, in which the vocal tract cross sectional area is directly obtained without estimating the short-time frequency spectrum of the speech wave, are proposed