摘要
为了消除扩频系统中的多径干扰,文章基于稳态零点不变的原则对多径估计延迟锁相环(MEDLL)进行研究及改进.文中给出了伪码跟踪环路的结构框图,并建立了多径干扰下环路的数学模型.在只考虑一路多径干扰信号的情况下分析了多径干扰信号对环路鉴相特性的影响.文中介绍了MEDLL,在保持环路稳态零点不变的情况下提出了零点不变估计延迟锁相环(ZFMEDLL),并将其相对于常规DLL、窄带DLL和MEDLL在稳态相位误差性能、噪声性能和实现复杂度方面进行了仿真比较.结果表明,ZFMEDLL相对于MEDLL在多径消除性能上有很大改进.
This paper discusses means to eliminate muhipath effects in spread spectrum systems. To this end the current multipath estimation delay locked loop （MEDLL） was investigated and improvements were proposed based on the zero-point fixed principle. A structural chart of the pseudo noise （PN） code tracking loop was developed, and a mathematical model of the signal tracking system in a muhipath environment was presented. While consider- ing only one duplicate path, we analyzed the influence of it on the loop~ discriminative ability. A MEDLL was in- troduced in this paper. In order to keep the loop stabilization zero point invariable we introduced zero-point fixed MEDLL （ZFMEDLL） , and compared the ZFMEDLL relatively with common DLL, narrow DLL and MEDLL in as- pects of stable phase error performance, noise performance and structural complexity of ZFMEDLL. The results in- dicated that ZFMEDLL, compared to MEDLL, significantly improves ability to resist muhipath effects.
出处
《哈尔滨工程大学学报》
EI
CAS
CSCD
北大核心
2009年第2期148-153,共6页
Journal of Harbin Engineering University
基金
国家自然科学基金资助项目(60704018)
关键词
扩频系统
伪码跟踪
多径干扰
多径估计延迟锁相环
鉴相特性
spread spectrum system
PN code tracking
multipath interference
muhipath estimation delay locked loop
discriminative character
