Effects of acoustic interaction between the subglottic and supraglottic cavities of the human phonatory system

Djeradi Rachida, Djeradi Amar

Abstract


The purpose of this work, is to describe the effects of the coupling of the subglottic and supra glottic cavities of the human phonatory apparatus. For this, we will determine and use the transfer function of the vocal tract evaluated owing to an exploration of the human phonatory system using an external excitation using a pseudorandom sequence; this method was developed by Djeradi et. al. 1991. This evaluation will be carried out on the basis of the following three conditions of the glottis: open glottis, closed glottis and variable glottis. One of the advantages of this method will be used, indeed, it is possible, at the time of the same expiry phase that corresponding to a sustained articulatory configuration, to record the signal of the sound itself and the useful signal for the measurement of the transfer function. The comparison of the various spectral data thus obtained highlights the subglottic effects of coupling on the one hand and shows that the conditions at the glottis have an influence on the resonances of the supraglottic cavities on the other hand. This enabled us highlight an increase in the value of the resonance frequencies, of the band-widths and a modification of the deviation between the resonances of the vocal tract. We have also noted the appearance of additional resonances peaks that can correspond to subglottic cavities During the second phase, we reproduced these effects by simulations on geometrical configurations obtained by the X- rays method performed on the same person and for the same configurations.

Keywords


Resonance; Acoustic interaction; External excitation; Geometrical configurations; Phonatory system; Pseudorandom sequences; Resonance frequencies; Second phase; Spectral data; Vocal-tracts

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