MPPSK/AM复合调制系统优化方案

Optimization Scheme of MPPSK/AM Hybrid Modulation System

摘要: 本文给出一种兼容AM广播的MPPSK/AM复合调制系统，为了提升数字信号的解调性能，需要增加MPPSK调制中的K值。而这同时也增加了数字信号与音频信号的频谱混叠，所以本文通过在发送端添加双带阻滤波器，使数字信号不占用音频信号的频段从而提升音频信号解调性能。并且根据贝叶斯公式得出的概率信息表格作为信道解码的软信息进行软判决译码进一步提升数字信号解调性能。

Abstract: This paper presents a MPPSK/AM Hybrid Modulation System which is compatible with the existing AM broadcast. While it causes the aliasing of digital signal and audio signal spectrum to increase the K value of MPPSK for the improvement of digital signal demodulation performance, thus double band-stop filter is added in the sender, making the digital signal not take up the audio signal frequency band to increase the audio signal demodulation performance. And soft decision decoding based on information table from Bayesian probability formula is obtained as soft information for channel decoder to further enhance the digital signal demodulation performance.