Voice simulation
B. Yegnanarayana, Jayant M. Naik, D. G. Childers · 1984
In this paper we describe a flexible analysis-synthesis system which can be used for a number of studies in speech research. The main objective is to have a synthesis system whose characteristics can be controlled through a set of parameters to realize any desired voice characteristics. The basic synthesis scheme consists of two steps: Generation of an excitation signal from pitch and gain contours and excitation of the linear system model described by linear prediction coefficients. We show that a number of basic studies such as time expansion/compression, pitch modifications and spectral expansion/compression can be made to study the effect of these parameters on the quality of synthetic speech. A systematic study is made to determine factors responsible for unnaturalness in synthetic speech. It is found that the shape of the glottal pulse determines the quality to a large extent. We have also made some studies to determine factors responsible for loss of intelligibility in some segments of speech. A signal dependent analysis-synthesis scheme is proposed to improve the intelligibility of dynamic sounds such as stops. A simple implementation of the signal dependent analysis is proposed.