基于周期图的π/4-DQPSK高速跳频系统同步方法

A Synchronization Method of π/4-DQPSK High-Speed Frequency Hopping System based on Periodogram

针对宽跳频带宽,多跳频点、相邻跳点频隙只有射频信号带宽的万分之一的跳频系统,提出一种改进的频率捕获周期图法和基于峰值检测的位同步方法。并且改进的频率捕获周期图法不需要导引码,结合信号能量检测和并行解调处理等方法,能够快速实现π/4-DQPSK高速跳频系统的同步与解调。仿真实验表明:该方法可以快速实现频率捕获并实现位同步,具有不受本地载频频差的影响和抗干扰能力强等特点,适用于高速跳频系统。

This paper proposes an improved method that is periodogram of acquisition of frequency and bit synchronization based on peak detect in order to fulfill the demand of frequency hopping system which is of wide frequency hopping bandwidth,multi-hopping points and adjacent frequency slots whose bandwidth is one of ten-thousandth of RF signal.This method that combined with signal energy detection,parallel demodulation and without Direct code can still achieve synchronization and demodulation ofπ/4-DQPSK high-speed frequency hopping system quickly.Experimental results show that the proposed method can achieve frequency of capture and bit synchronization accurately.Meanwhile,it has the characteristic that is no interference by local carrier frequency and strong anti-interference ability so that is suitable for high-speed frequency hopping system.