Matlab直扩MSK系统的载波同步技术研究

摘要载波同步在通信系统中，起着不可忽视的作用。在MSK的信号处理过程中，相干解调是至关重要的一部分，而载波同步技术又是相干解调里的不可或缺的一环，对解调的结果起着决定性作用。载波同步分为频率同步和相位跟踪，频率同步主要解决的是多普勒频偏问题，相位跟踪主要解决的是相位偏差问题。在实际操作中，特别是高动态环境下，频偏和相偏会影响解调的过程和结果。为了解调原始信号，本文使用了提取频差和相差，同时作相应补偿。34101
本文介绍了基于FFT变换的多普勒频偏提取算法用于频偏估计，并且通过Matlab程序进行了算法验证。而后，本文分析了几种高精度频偏估计方法，并且在相互之间做出比对，同时，本文对MSK信号的costas环载波相位跟踪算法的原理和解决方法做出了介绍，并且得出了其鉴相特性曲线。在文章最后，仿真了相位跟踪过程以及分析了环路跟踪性能。
关键词   载波同步相位跟踪   Matlab   频率同步
毕业论文设计说明书外文摘要
Title    The Research on Carrier Synchronization Of DS MSK System
Abstract
Carrier synchronization plays a considerable role in a communication system.Carrier synchronization is a key technique of coherent PSK signal demodulation,which is directly related to the result of demodulation.Carrier synchronization is pided into frequency synchronization and phase tracking,frequency synchronization is mainly used to solve the issues of dopper frequency offset,meanwhile,phase tracking is mainly used to solve the issues of phase deviation.In practice,especially in high dynamic environment,the frequency deviation and phase deviation will affect the demodulation process and the result.To demodulate original signal ,I extracted the frequency offset and the phase deviation ,and made corresponding compensation .
For the frequency offset estimation, this paper described the algorithm based on FFT transformation to extract Doppler offset , and then made a verification on Matlab.After that,I analyzed several kinds of high precision frequency estimation method,and made a comparison between each other , For phase tracking, the paper described the method based on Costas-loop ,and derived the characteristic curves of phase detector.Finally, I simulated the process of phase tracking on Matlab ,and analyzed the performance of loop tracking .
Keywords    Carrier Synchronization    Frequency Synchronization   Phase Tracking    Matlab
目   次
1 绪论    1
1.1 研究背景及意义    1
1.2 国内外研究现状    1
1.3 本文的主要工作    3
2 扩频通信    4
2.1 扩频通信的原理    4
2.2 直接扩频通信    4
2.3 伪码序列    5
2.4 本章小结    6
3 直扩MSK信号的调制与解调    7
3.1 直扩MSK信号调制基本原理    7
3.2 仿真参数设置    10
3.3 仿真结果    10
3.4 直扩MSK信号的解调    11
3.5 本章小结    12
4 直扩MSK信号的载波同步    13
4.1 频率同步    13
4.2 相位跟踪    24
4.3 本章小结    31
结论    32
致谢    33 Matlab直扩MSK系统的载波同步技术研究:http://www.751com.cn/tongxin/lunwen_31514.html