Pole-zero determination of the vocal-tract transfer function

Abstract

This paper describes an effort in the accurate estimation of the pole- and zero-location (frequency and bandwidth). The procedure is performed by an appropriate computer program. As the spectrum is plotted on a computer display, the human operator is given the possibility to mark areas of interest by light pen. From the spectrum a first estimate of the frequency and bandwidth is evaluated by calculating the maximum (or minimum) of the transfer function in a given area and the width of its 3-dB slope. A subsequent variation of the frequency and bandwidth leads to an accurate evaluation of the pole or zero location in the s-plane. The variation strategy used by the computer and results are presented.