Simultaneous modeling of EGG, PGG, and glottal flow
Bert Cranen · The Journal of the Acoustical Society of America · 1988
For obtaining insight into basic aspects of voice quality, an adequate parametrization of the voice source is mandatory. Theoretical studies have shown that changes of the glottal geometry in the direction of flow are an essential prerequisite for self-oscillation of the vocal folds. Thus it is attractive to use stylized glottal shapes as a basis for voice source parametrization, and try to extract the geometry parameters (semi-) automatically from indirect measurements like the electroglottogram (EGG) and photoglottogram (PGG). Titze [J. Acoust. Soc. Am. 75, 570–580 (1984)] presented a model with which he simulated simultaneous measurements of PGG and EGG. It is thought that EGG and PGG are not sufficient for inferring all relevant aspects of glottal geometry. In this paper, it is shown that glottal flow supplies additional information that can be used to impose extra restrictions on the model parameters. Simulations show that when simultaneously modeling EGG, PGG, and glottal flow, it is crucial to assume that the opening of the vocal folds occurs more gently than the closing. Implications of this finding for the description of vocal fold movements in modeling EGG and PGG are discussed.