Low bit-rate, good-quality speech coding is one of the fundamental goals of today's speech processing research. Present-day coding techniques, like APC and ATC, are able to achieve good-quality transmission only down to about 12 kb/s. Below this rate, their quality degrades rapidly. On the other hand, the various kinds of vocoders, which operate up to about 5 kb/s, have inherent quality limitations which cannot be overcome by an increase of the bit rate. In this paper, a new coding scheme is presented, which is based on a recently developed spectral model for nonstationary voiced speech, and it forms the basis of a waveform coder and a vocoder which are introduced in this paper, and which share the same basic structure. Experimental results are presented, which show that both systems yield significant bit-rate reductions relative to present-day schemes of equivalent quality.
[1]
José M. Tribolet,et al.
A model for short-time phase prediction of speech
,
1981,
ICASSP.
[2]
B. Atal,et al.
Improved quantizer for adaptive predictive coding of speech signals at low bit rates
,
1980,
ICASSP.
[3]
M. R. Schroeder,et al.
Adaptive predictive coding of speech signals
,
1970,
Bell Syst. Tech. J..
[4]
Ronald E. Crochiere,et al.
Frequency domain coding of speech
,
1979
.
[5]
R. Cox,et al.
Real-time simulation of adaptive transform coding
,
1981
.
[6]
J. Flanagan.
Speech Analysis, Synthesis and Perception
,
1971
.
[7]
José M. Tribolet,et al.
A spectral model for nonstationary voiced speech
,
1982,
ICASSP.