Preliminary experiences in using automatic inverse filtering of acoustical signals for the voice source analysis

Abstract

A new straightforward glottal wave analysis method, called Iterative Adaptive Inverse Filtering (IAIF), is presented. The method is based on the separated speech production model that consists of three processes: The glottal excitation, the vocal tract and the lip radiation effect. In order to estimate the vocal tract transfer function the effect of the source to the speech spectrum is first estimated with an iterative procedure. After eliminating the estimated glottal contribution, the vocal tract transfer function is estimated using linear predictive analysis (LPC). The estimate for the glottal excitation is finally obtained by cancelling the effects of the vocal tract and lip radiation by inverse filtering. The performance of the new algorithm is verified and compared to two other LPC-based glottal wave analysis methods using synthetic vowels. It is shown that the IAIF-method is able to give a fairly accurate estimate for the glottal excitation. The results of the analysis of natural speech using the IAIF-method are also discussed.

Key Words:

• inverse filtering
• glottal flow