增强型全速率语音编码的原理及实现

在无线通信系统中，语音压缩编码起着非常重要的作用，因为它在很大程度上决定着合成话音的质量和系统容量。为了提高话音质量，GSM提出了增强型全速率（EFR）语音编码方案。它在LPC声码器的基础上，采用了A－B，S和VQ等技术，编码信息中既包含若干语音特征参量又包括部分波形编码信息。因此，能提供高质量的编码，且比特速率压缩到12.2kbps,为TD－SCDMA移动通令系统提供了一咎可行的语音编码方式。笔者从语音编码的基本概念出发，详细地介绍了EFR语音编码的原理及代数码本搜索实现技术。

Principle and Algorithm lmplement of Ehanced Full-rate Speech Coding

Speech coders have assumed considerable importance in radio communication systems as their performance,to a large extent,determines the quality of the recovered speech and the capacity of the system.In order to enhance the quality of speech,GSM puts forward the EFR speech coding algorithm.It bases on the LPC coder,the encoding information includes not only speech feature parameters,but also some wave information,due to the application of A_B_S and VQ. It can afford TD_SCDMA a feasible encodec algorithm,for its high quality and the 12.2kbps speech rate. This article starting with the principal concepts of speech coding,introduces the pringciple of speech coding and ACELP algebraic code book search algorithm in detail.