Abstract: The article introduces the principle of the Direct Vector Quantization（DVQ） algorithm which is applied to emulation encoder module and codebook search module in LD-CELP speech coding algorithm.The synthesis filter in emulation encoder module is replaces by the inverse perceptual filter，removing the operation of impulse response h（n） in the codebook search module.The result show that the DVQ algorithm reduced its complexity and improved the efficiency of codebook search and the time is 3~5 second less than that of LD-CELP algorithm while keeping the quality.

Key words: vector quantization, codebook search, speech coding

摘要： 介绍了一种降低码书搜索复杂度的方法-直接矢量量化（DVQ）方法，将其应用于LD-CELP语音编码算法中的仿真译码器模块和码书搜索模块，用感觉加权逆滤波器代替仿真译码器模块中的综合滤波器，去除了码书搜索模块中冲激响应h（n）的运算。实验结果表明，利用直接矢量量化方法简化了码书搜索算法的复杂度，提高了码书搜索算法的效率，在运算时间方面比原始LD-CELP算法快3 s~5 s，同时保持了原编码算法合成语音的音质。

关键词: 矢量量化, 码书搜索, 语音编码