Inverse Filtering Techniques in Speech Analysis

This paper reviews certain speech analytical techniques to which the label 'inverse filtering' has been applied. The unifying features of these techniques are presented, namely:1. a basis in the source-filter theory of speech production,2. the use of a network whose transfer function is the inverse of the transfer function of one or a combination of the articulatory system filters to modify the speech wave either in the time domain or in the frequency domain.However their differences, which lie in the particular system filter being inverted and in the manner of realisation. provide a basis for the classification adopted in the paper which is as follows: (1) inverse vocal tract analogue filtering. (2) inverse vocal tract digital filtering. (3) direct inverse glottal filtering. (4) linear predictive coding. An assessment of the comparative usefulness of inverse-filtering in contemporary speech studies is given