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.
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
关键词
半速率语音编码
码激励线性预测
数字信号处理
Half rate speech coding, Code excited linear prediction, Linear spectrum pairs parameters, Friction delay, Digital signal processing