TITLE:        Generalized predictive trellis coded quantization of speech
AUTHORS:      M. W. Marcellin and T. R. Fischer
CONFERENCE:   IEEE International Phoenix Conference on Computers and 
	      Communications, Phoenix, Arizona, March 1989
ABSTRACT:
Trellis coded quantization (TCQ) is incorporated into a generalized 
predictive (noise feedback) coding structure for encoding sampled speech.  
Adaptive residual encoding and adaptive prediction are used to obtain 
signal-to-noise ratios (SNR) in the range of 17.5 to 21.6 dB for encoding 
sampled speech with 2 bits per sample (16 Kbits per second). Spectral 
noise shaping is achieved with this coding structure by using a bandwidth
expanded version of the predictor as a noise feedback filter.  This has the
effect of reducing the SNR of the encoding by a small amount but 
improving the perceptual quality of the reconstructed speech.  The 
reconstructed speech obtained from this system can be described as being of
excellent communications quality.
 
A modified Viterbi algorithm is used for the trellis search to allow 
flexibility in the choice of symbol release rule.  The effects of varying 
the encoding delay and the number of symbols released per trace-back 
on system performance and complexity are investigated.  We show that 
excellent SNR performance can be obtained with modest encoding delays.