脉冲编码调制/调频（Pulse Code Modulation/ Frequency Modulation， PCM/ FM）体制具有精度高、遥测格式灵活多变等特点，在导弹和航天器遥测中有着广泛应用。针对 PCM/ FM 信号传统解调方法存在门限较高的问题，利用其相位连续特性采用了一种最大似然检测方法---多符号检测（Multi Symbol Detection， MSD）。以 MSD 算法为基础，研究 PCM/FM 信号解调算法，针对解调过程中参数的选择与优化进行研究。通过理论推导和 MATLAB 仿真，分析检测序列长度、码元采样点数等参数对误码率的影响，可以针对不同的解调需求灵活的加载最优的参数，对实际应用起到理论指导作用。%Pulse Code Modulation/ Frequency Modulation ( PCM/ FM) system has some virtues as high-precision and varied forms,which promise its wide use in missiles and spacecraft telemetry.In view of the traditional demodulation method with high thresh-old,a multi-symbol detection (MSD) approach is raised in consideration of PCM/ FM signal phase continuous characteristic.Based on MSD algorithm,a method is introduced to demodulate PCM/ FM signal.And discussion focuses on the selection and optimization of the parameters during demodulation process. Through theoretical derivation and the MATLAB simulation, the impact of the length of detection sequence and the number of sampling points in each symbol is analyzed,in order to choose flexible and optimal parameters for different demodulation needs.The research has both theoretical and practical values.
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