一种改进的6.25 kbit/s GSM半速率语音编码方案  

A Scheme of GSM Half rate Speech Coding at Speed of 6.25 kbit/s

作　　者：冯玉文[1] 周月臣[1] 

机构地区：[1]南京邮电学院通信工程系

出　　处：《南京邮电学院学报》1998年第4期23-26,共4页Journal of Nanjing University of Posts and Telecommunications(Natural Science)

基　　金：邮电部科技司资助

摘　　要：在采用ＣＥＬＰ（码激励线性预测）作为ＧＳＭ半速率编码方案的基础上，对ＣＥＬＰ的三个主要组成部分分别进行了改进，在ＬＳＰ（线谱对）参数分析中提出了将求解和量化相结合的快速算法；在ＬＴＰ（长时预测）分析的分数延迟搜索中，采用逐步缩小搜索范围的方法；在随机码本搜索中，采用高斯重叠稀疏码本。这些措施大大降低了计算量，从而在保证合成语音质量的基础上能够采用单片ＤＳＰ实时实现整个ＣＥＬＰ编译码器。Three main parts of CELP on which GSM half rate speech coding is based are improved respectively in this paper. A fast algorithm combined quantization with roots solving is also proposed in LSP parameters prediction. A method of decreasing the search range step by step is used in LTP with friction delay. A Gaussian over lapped and clipped codebook is used in codebook search. The improvements result in a significant reduction in calculation complexity, so that the whole CELP codec can be real time implemented with a single DSP chip without degradation of the reconstructed speech.

关 键 词：半速率语音编码 码激励线性预测 数字信号处理 

分 类 号：TN911.72[电子电信—通信与信息系统] TN912.3[电子电信—信息与通信工程]