VECTOR QUANTIZER METHOD AND APPARATUS

摘要

A Vector-Sum Excited Linear Predictive Coding (VSELP) speech coder (200) provides improved quality and reduced complexity over a typical speech coder. VSELP uses a codebook (201) which has a predefined structure such that the computations required for the codebook search process can be significantly reduced. This VSELP speech coder uses single or multisegment vector quantizer of the reflection coefficients based on a Fixed-Point-Lattice-Technique (FLAT). Additionally, this speech coder uses a pre-quantizer to reduce the vector codebook search complexity and a high-resolution scalar quantizer to reduce the amount of memory needed to store the reflection coefficient vector codebooks. Resulting in a high quality speech coder with reduced computations and storage requirements.