一种改进型CVSD编译码器的设计方法  

An improved design method of CVSD coder and decoder

作　　者：邓勇 DENG Yong(The 10th Research Institute of CETC,Chengdu 610041,China)

机构地区：[1]中国电子科技集团公司第十研究所,四川成都610041

出　　处：《微电子学与计算机》2023年第3期99-106,共8页Microelectronics & Computer

基　　金：国家重点研发计划(2017YFC1404900)。

摘　　要：在军事无线、卫星、水下等环境复杂的语音通信领域,连续可变斜率增量CVSD编码以实现简单、纠错能力强等特点被广泛应用.然而,标准CVSD编码的混合双积分增量调制系统存在不稳定现象,面对信道突发误码,抗干扰能力不足容易导致语音质量的下降.设计一种改进型CVSD编译码器,利用语音编码的延迟性和语音数据的相关性,通过连续跟踪多条胳径进行误差度量,采用合适的失真准则从多种可能的编码输出中找到最佳输出序列,在确保重建语音波形的基础上,实现对语音信号的有效编码,从而解决混合双积分增量调制系统不稳定的问题;同时,通过改进的数字压扩器提高编译码的信噪比,解决由查表法引入的误差累积问题,进一步提升CVSD编码在特殊信道中的适应能力.最后基于某水下语音通信终端对改进的CVSD编译器可用性进行测试评估.实验表明,本文提出的改进型CVSD编译码器在稳定性上相比标准CVSD编码抗误码能力更强,语音质量更好,具有较高的使用及推广价值.CVSD coding is widely used in the field of speech communication in military wireless,satellite,underwater and other complex environments for its simple implementation and strong error correction ability.However,the hybrid double integral delta modulation system with standard CVSD coding is unstable.In the face of channel burst error,the lack of anti­interference ability easily leads to the degradation of speech quality.An improved CVSD coder and decoder is designed.Based on the delay of speech coding and the correlation of speech data,the error measurement is carried out by continuously tracking multiple paths,and the optimal output sequence is found from a variety of possible coding outputs by using appropriate distortion criteria.The instability of the hybrid double integral delta modulation system can be solved.At the same time,the improved digital diffuser is used to improve the signal-to-noise ratio of coding and decoding,solve the error accumulation problem introduced by table lookup method,and further improve the adaptability of CVSD coding in special channels.Finally,the usability of the improved CVSD compiler is tested and evaluated based on an underwater voice communication terminal.The experimental results show that the improved CVSD encoder and decoder has stronger error resistance and better speech quality than the standard CVSD encoder in terms of stability,and has higher application and promotion value.

关 键 词：连续可变斜率增量 误码率 语音质量 最佳路径跟踪 数字压扩 

分 类 号：TN924.2[电子电信—通信与信息系统]