基于最大似然估计的PCM-FM信号软件解调方法  

Method of Software Demodulation for PCM/FM Signal Based on MLE

作　　者：陈源[1,2] 王元钦[2] 郑海昕[2] 

机构地区：[1]江南计算技术研究所,无锡214083 [2]解放军装备学院,北京101416

出　　处：《系统仿真学报》2013年第5期945-949,956,共6页Journal of System Simulation

基　　金：装备预研项目(9140A24070509KG02)

摘　　要：利用软件实现信号处理已经成为未来信号处理的发展趋势。针对传统PCM-FM信号在低信噪比下难以实现有效解调的问题,结合PCM-FM信号前后符号之间存在相位记忆性的特征,提出了基于最大似然估计的软件解调方法。描述了最大似然估计模型的建立和维特比搜索路径的实现;同时结合软件中数据块式的传输模式和维特比路径搜索的特点,研究了一种基于数据冗余的软件解调实现方式,充分利用了计算机系统并行处理性能,提高了算法的运行效率;并以算法误码率为指标,比较了软件似然估计算法与传统鉴频解调的性能,结果表明在误码率10-2处时算法能够得到约3dB的解调增益。Using software for real-time signal processing is the trend of digital signal processing. According to the problem of demodulation for low SNR PCM/FM signal, the method of software demodulation based on Maximum Likelihood Estimator （MLE） was proposed. The model of MLE and the route of Viterbi were analyzed; A method of parallel processing based on the redundant data was proposed according to the characteristics of the data block transmission mode in software and route of Viterbi, which made good use of the parallel capability of computer, improved the parallel efficiency and was convenient to be realized by software; The Bit Error Ratio （BER） performance is compared between software method of MLE and traditional frequency detector. The results show 3dB demodulation gain could be achieved when BER is 10-2.

关 键 词：PCM—FM解调 最大似然估计 维特比路径 软件化 并行处理 

分 类 号：TP334[自动化与计算机技术—计算机系统结构]