Vector quantization of speech line spectrum pair parameters and reflection coefficients

Methods are presented for intraframe encoding of line spectrum pairs. A two-stage vector quantizer-lattice vector quantizer (VQ-LVQ) has a 2-3 b/vector performance advantage over the split vector quantizer, and can save 1-3 b/vector, compared to multistage vector quantization, depending on the number of stages and the number of survivors retained at each stage. The vector quantizer-lattice vector quantizer has a moderate computational complexity. Among three trellis codes considered, trellis-coded vector quantization with nonlinear prediction provides line spectrum pair encoding performance similar to the split vector quantizer. Hybrid transformations are developed for encoding the reflection coefficients using vector quantization, and offer a small encoding advantage over the commonly used arcsine transformation and log area ratios.