A structured fixed-rate vector quantizer derived from a variable-length scalar quantizer. II. Vector sources

For Pt.I see ibid., vol.39, no.3, p.851-67 (1993). The fixed-rate scalar-vector quantizer (SVQ) for quantizing stationary memoryless sources is extended to a specific type of vector source in which each component is a stationary memoryless scalar subsource independent of the other components. Algorithms for the design and implementation of the original SVQ are modified to apply to this case. The resulting SVQ, referred to as the extended SVQ (ESVQ), is then used to quantize stationary sources with memory (with known autocorrelation function). Numerical results are presented for the quantization of first-order Gauss-Markov sources using this scheme. It is shown that the ESVQ-based scheme performs very close to entropy-coded transform quantization while maintaining a fixed-rate output and outperforms the fixed-rate scheme that uses scalar Lloyd-Max quantization of the transform coefficients. It is also shown that this scheme performs better than implementable vector quantizers, especially at high rates