PCM/PPK再入遥测系统性能分析

Analysis of the Performance of PCM/PPK Reentry Telemetry System

PCM/PPK再入遥测系统是一种多进制脉冲位置调制系统,具有抵抗码间干扰能力强、能量效率高的特性。在该系统中,码元之间不是相互独立的,基于PCM码的群码特性,分析了在择大检测下PCM/PPK系统的误码性能和误差特性,并与固定门限判决下的误码性能和误差特性进行了比较,结果表明,在小信噪比时择大检测劣于固定门限检测,而在大信噪比时优于固定门限检测。

PCM/PPK reentry telemetry system is a multi-level pulse position modulation system with a strong ability of anti-inter-symbol interference and high energy efficiency.BER and error characteristics performance of the system is analyzed in detection of the maximum value based on the fact that symbols of the system are not independent with each other,utilizing the feature that codes transmitted are group codes.The performance is compared with that in decision of fixation threshold.The result shows that the BER performance in detection of the maximum value is less than the decision of fixation threshold with small signal-to-noise ratio,but BER performance in detection of the maximum value decision is better than the decision of fixation threshold with large signal-to-noise ratio.