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MATLAB直扩MSK系统的码同步技术研究

时间:2019-01-12 15:16来源:毕业论文
直扩MSK信号系统的结构并对各个部分功能进行了简单分析介绍。给出了一般该信号的调制方法,利用MATLAB进行仿真检验其正确性。另外,还通过仿真出该信号的各种特性曲线

摘要MSK调制是许多种数字调制方式中的一个。数字调制是将数字信号转换为模拟信号的过程其特点是将其转换为与传输信息通道的特点相匹配的的波形。调制过程就是输入数据控制(键控)载波的幅度、频率和相位。MSK信号有十分多的优点与长处这样也决定了其特别适合在许多以往的调制系统所不能解决的系统之中,例如功率受限以及存在非线性失真、多普勒频移和多径衰落的无线通信领域。32613
通过对各种文献的了解,简单的介绍了直扩MSK信号系统的结构并对各个部分功能进行了简单分析介绍。给出了一般该信号的调制方法,利用MATLAB进行仿真检验其正确性。另外,还通过仿真出该信号的各种特性曲线,进一步来验证信号产生的合理性和有效性。直扩MSK信号的捕获。着重讨论了如何将其相位差初步锁定在正负Tc/2之内,并且介绍了消除大多普勒频偏的方法。直扩MSK信号的跟踪。介绍了如何实现精确同步的方法。
关键字  扩频  MSK  捕获  跟踪  MATLAB
毕业论文设计说明书外文摘要
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. 源自/六^维:论"文;网(加7位QQ3249~114 www.lwfree.cn
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  匹配滤波器原理    12
3.3  基于奈曼-皮尔逊准则的门限判决    14
3.4  大多普勒频谱下的码捕获    16
3.5  本章小结    19
4  码跟踪技术的研究    20 MATLAB直扩MSK系统的码同步技术研究:http://www.lwfree.cn/tongxin/20190112/29295.html
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