基于MPPSK调制的数字对讲机系统

The Digital Intercom System Based on MPPSK Modulation

为改善数字对讲机频谱资源紧张的趋势,本文提出一种基于MPPSK调制的数字对讲机系统,采用MPPSK体制作为数字对讲机的物理层调制解调方式,利用现有数字对讲机通信体制中的频谱空隙,“插空”传输高速码流。接收机通过对MPPSK收发混叠信号的冲击滤波和相干处理后,结合“码率域”滤波和带阻滤波消除其他用户干扰并可靠解调出MPPSK接收信号。本系统对相邻频道的其他数字对讲机信号干扰很小,对邻频或同频干扰隔离度高,传输码率。

In order to improve the trend of digital radio spectrum resources nervous, this paper proposes a digital intercom system based on MPPSK modulation, which uses MPPSK system as digital radio modem in the physical layer and “fill-in” transmit high data rate stream in existing spectral gap. After impact filtering and coherent processing, the interferences from other intercom users are filtered out with “rate domain” filtering and band-stop filtering, and the receiver can get reliable demodulation of MPPSK signal. The system has little interference compared with other digital radio systems, and has got high interference isolation with adjacent frequency or same frequency and high transmission rate.