title: Smoothness of an equation for the glottal flow rate versus the glottal area.
abstract: This letter proposes a correction to an equation by Titze [J. Acoust. Soc. Am. 75, 570-580 (1984)] for the volume velocity of the glottal air flow given the glottal area and other laryngeal parameters. It shows that the equation produces non-differentiable waveforms at the instants of glottal closure and opening, if the glottal area is also not differentiable at those instants. By adding an air viscosity term to the equation, twice-differentiability is obtained. Also, the letter corrects a sign error in the original formulation.
authors.affiliation: Department of Computer Science, University of Brasilia, Brasilia, Federal District, 70910-900, Brazil.
authors.forename: Jorge C
authors.initials: JC
authors.lastname: Lucero
authors.affiliation: Laboratories of Image, Signal Processing and Acoustics, Faculty of Applied Sciences, Université Libre de Bruxelles, 50, Avenue Franklin D. Roosevelt, B-1050, Brussels, Belgium.
authors.forename: Jean
authors.initials: J
authors.lastname: Schoentgen