一种基于GMSK调制的直扩系统的设计  

Design of DSSS system based on GMSK modulation

作　　者：毛维同 郑林华[1] 陈超然[1] 王坦[1] 

机构地区：[1]国防科学技术大学电子科学与工程学院,湖南长沙410073

出　　处：《现代电子技术》2015年第19期12-14,18,共4页Modern Electronics Technique

摘　　要：通过介绍直接序列扩频(DSSS)+GMSK调制的扩频系统的基本原理,分析了GMSK调制相对于MSK调制的优越性。对接收端信号先解扩后解调能有效利用扩频增益,提高系统性能。提出一种零中频直接相关的解扩解调方法。该方法在接收端先将本地扩频码进行GMSK调制,再与接收信号作相关,可以实现接收端伪码的捕获以及后续的解扩解调工作。通过Matlab仿真可以得到,在低信噪比环境下,该方法比先解调再解扩的方法有更好的误码性能。The fundamental of spread spectrum system with direct sequence spread spectrum（DSSS）＋GMSK modulation is introduced,the superiority of GMSK modulation relative to MSK modulation is analyzed. The receiving terminal signal conducted with demodulation after despreading can utilize the spread spectrum gain effectively and improve system performance. The de？spreading and demodulation method which is directly related to zero intermediate frequency is proposed. The local spread spec？trum codes are modulated with GMSK in the receiving terminal,and the modulated nodes are correlated with the received signal. The capture of pseudo code in the receiving terminal and the following dispreading and demodulation work can be realized. Mat？lab simulation results show that this method has better BER performance than the method of demodulation before despreading in low SNR environment.

关 键 词：直接序列扩频 GMSK调制 匹配滤波 解扩解调 

分 类 号：TN911-34[电子电信—通信与信息系统]