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数字移动通信近几年来得到长足的发展,而语音低码率编码是其中一项关键技术.本文提出一种脉冲自适应码本激励编码方案.该方案将规则脉冲激励算法和码本激励算法有机地相结合,采用新的有效码本结构,降低码字的维数,提高码字的效率,另外,在最佳激励搜索上采用了脉冲自适应搜索方式,避免了全寻的工作方式,使得码本搜索的计算量大大降低。通过计算机模拟结果表明,该编码方案和美国EIA公布的编码算法相比具有计算量小,所占储存空间少而合成音质几乎不下降等优点.在8Kb/s PACELP能够合成出令人满意的语音质量。而这一切又保证了PACELP算法可以在一块TMS320 C25上实现。
Digital mobile communication has made great progress in recent years, and speech rate coding is one of the key technologies.In this paper, a pulse adaptive codebook excitation coding scheme is proposed.This scheme combines the rule-based pulse excitation algorithm and the codebook excitation algorithm The new effective codebook structure is adopted to reduce the dimensionality of the codeword and improve the efficiency of the codeword. In addition, a pulse adaptive search method is adopted on the best excitation search, avoiding the working way of full search, The amount of codebook search is greatly reduced. Computer simulation results show that the proposed coding scheme has the advantages of low computational complexity, less storage space and less degradation of synthesized sound quality compared with the coding algorithm proposed by EIA in the United States. The PACELP at 8Kb / s can synthesize a satisfactory speech quality. And all this ensures that the PACELP algorithm can be implemented on a TMS320 C25.