Nontactile estimation of glottal excitation characteristics of voiced speech

A record of voiced speech is LPCanalysed. It is also partitioned into a sequence of short signals, each containing a single glottal pulse. Each short signal is taken to be the convolution of a component varying from one short signal to the next and an invariant component, corrupted by a significant but not overwhelming contamination, i.e. noise plus all other imperfections. The invariant component, which is initially estimated by shift-and-add processing, is the multiple convolution of the invariant responses of the recording apparatus, the speaker´s lips and vocal tract (plus nasal tract and soft palate) and the speaker´s average glottal excitation. This initial estimate, which is characteristic of the glottal excitation, is iteratively refined by a computational procedure which makes use of the LPC coefficients. The procedure, which checks its own numerical convergence, is illustrated by presenting results for six different speakers and for a single speaker under varying conditions.