直扩MSK系统的码同步技术研究+MATLAB仿真

摘要本文将扩频通信技术与最小频移键控信号（Minimum Shift Keying）技术相结合，讨论研究直接序列扩频MSK技术（简称直扩MSK技术），综合了二者，兼具信道带宽大、保密性好及抗干扰能力强等特点，在军事和卫星通信领域运用十分广泛。而码同步的研究是信号解扩的必要条件，所以，研究直扩MSK系统的码同步技术具有重要意义。
本文首先推导出直扩MSK信号的基带表示，实现其信号产生。重点在研究直扩MSK信号的码同步技术。码同步技术包括粗同步——码捕获技术，和精同步——码跟踪技术。
码捕获技术主要采用了匹配滤波技术，门限的设置主要基于奈曼-皮尔逊信号检测准则。本文研究还发现大多普勒频偏对匹配滤波的相关峰具有一定的影响，针对此现象采用基于FFT的频偏估计法来消除频偏。码同步技术采用了全数字非相干超前-滞后延迟锁相环，系统闭环以消除相位误差。本文基于MATLAB仿真来讨论环路的相关性能，如环路抖动等。19117
关键字扩频 MSK 捕获跟踪 MATLAB
毕业设计说明书（论文）外文摘要
Title Research on code synchronization technology for DS-MSK system
      Abstract
This paper combines Spread spectrum communication technology(SSC) and the Minimum frequency Shift Keying signal, discussing direct sequence spread spectrum MSK technology (hereinafter referred to as direct expansion MSK) technology. It has a combination of the two advantages, with all the wide channel bandwidth, the good secrecy characteristics and strong anti-jamming capability, widely used in the field of military and satellite communications. The code synchronization research is necessary for signal dispreading. So, the study of direct expansion MSK system code synchronization technology is of great significance.
This paper derives the baseband expression of MSK signal first, realizing its signal, focusing on the study of the spread spectrum MSK signal code synchronization technology, including coarse synchronization - code capture technology, and fine synchronization - code tracking technology.
Code capture technology mainly adopts the matched filtering technique. Threshold Settings bases mainly on Neyman-Pearson signal detection criterion. In this paper, the research also finds that under the large doppler frequency offset, matched filtering correlation peak has a certain impact. Thus, frequency offset estimation based on FFT is adopted. Code synchronization technology uses the digital non-coherent ahead–lay delay phase-locked loop. This paper also discusses the performance of the loop, such as loop jitter, based on the MATLAB simulation.
Keywords spread spectrum MSK capture tracing MATLAB

目次
1 绪论   1
1.1 课题研究的背景   1
1.2 国内外研究动态   1
1.3 论文的主要工作及章节安排   2
1.4 本章小结   3
2 直扩MSK调制原理   4
2. 1 扩频原理   4
2.2 直扩MSK信号调制原理   5
2.3 直扩MSK信号的产生   8
2.4 本章小结   11
3 直扩MSK的码捕获   12
3.1 直扩MSK接收机   12
3.2 匹配滤波器同步捕获基本原理   12
3.3 基于奈曼-皮尔逊准则的门限判决   14 直扩MSK系统的码同步技术研究+MATLAB仿真:http://www.youerw.com/tongxin/lunwen_10339.html