Publication Abstract

Weinstein, C. J. and Oppenheim, A. V., Predictive Coding in a Homomorphic Vocoder, IEEE Trans. on Audio and Electroacoustics, September 1971, Vol. AU-19, No. 3, pp. 243-248.

Abstract

Application of a type of predictive coding to the channel signals of a homomorphic vocoder has produced sizable bit rate reductions. With only slight degradation in speech quality, reduction (for the spectral envelope information) from 7800 to 4000 bits/s was achieved. A technique for obtaining the formant frequencies from the predictive coding parameters is described; this approach promises further bit rate reductions. As a by-product of this study of predictive coding, direct and cascade form speech synthesizers are compared on the basis of differing quantization effects.