EXCITATION CODEBOOK SEARCH METHOD IN VOICE CODING SYSTEM

摘要

PURPOSE: An excitation codebook search method in a voice coding system is provided to find an optimal or sub optimal code vector within a short period of time so as to improve coding performance of the voice coding system. CONSTITUTION: A voice signal frame is divided into a plurality of sub-frames, each sub-frame is split into a plurality of sub-groups, and pulses are searched in each sub-frame in order to generate an excitation signal used in a composite filter of a voice coding system. A predetermined number of pulses having magnitudes other than zero are obtained from each sub-group and generated as an initial vector. A pulse combination including at least one pulse is selected from the pulses of the initial vector. The pulses of the selected pulse combination are substituted by other pulses of each sub-group(205). The selection and substitution steps are repeated for all pulses of the initial vector(205).