Computation of vocal tract area functions

This paper describes a noniterative algorithm for synthesizing vocal tract area functions. The vocal tract is parameterized in terms of a few of the low-frequency poles and zeros of the driving point impedance at the lips and the length of the tract. Using an asymptotic relation, ship for a Sturm-Liouville system, additional critical frequencies are supplied on the basis of the length parameter only. The algorithm, which is due basically to Richards, yields a structure which is a cascade of equal length uniform tubes of differing cross sectional areas. The number of such tubes depends upon the number of critical frequencies specified. Vowel data of Fant is used to test the algorithm. It is found that the synthesized area functions are good approximations to the actual ones. Because of the noniterative nature of the algorithm, execution time is very small.