MSK调制解调算法研究与实现

摘要：在无线数字通信中，最小频移键控（MSK）有广阔应用空间。尤其在短波、微波和卫星通信中，MSK凭借其包络恒定、相位连续、频谱带宽窄等优势被广泛使用。现阶段，在短波中宽带高速率MSK发展已较为完善。但用于窄带低速率的调制技术还待进一步研究。

本课题以MSK为研究对象，主要探究其可达到更好性能的调制与解调的算法。分别探究了正交调制、相位调制及相位叠加的调制算法。在解调方面，探究了延时相干解调法，并改进得到相干延时判决法。通过算法的实现与仿真，以上两种算法的误码率性能并未有明显的改善。原因在于解调对于载波定时同步要求较高。最后，实现了离散傅里叶变换的解调方法。通过对比得出，应用该解调方法的系统的误码率性能较好。

关键词 MSK；调制；解调； MATLAB

毕业设计说明书外文摘要

Title Research and Implement of MSK Modulation And Demodulation

Abstract：In the field of the wireless digital communication, the Minimum Frequency Shift Keying (MSK) has been widely used especially in terms of short-wave, microwaves and satellite communication, boasting of its constant envelope, continuous phase and narrow spectral bandwidth. Currently, the development of the high-speed MSK with a wide bandwidth in the short-wave has been improved. However, the modulation technology of low-speed MSK with a narrow bandwidth needs further research.

The article mainly studies MSK, focusing on the algorithm which can carry out better modulation and demodulation. The modulation algorithms of quadrature modulation, quadrature phase modulation and phase superposition are studied respectively. In terms of demodulation, the delayed coherent demodulation is researched and a coherent time-delay judgment is improved. Besides, through the realization and simulation, the bit error rate of the two above-mentioned algorithms fails to have a distinctive improvement due to the higher demanding of carrier timing synchronization. Finally, the demodulation algorithm based on DFT is realized. By comparison, the system in this method can provide better BER performance.

Keywords MSK modulation demodulation MATLAB

1.引言…1

1.1课题研究背景与意义…1

1.2 章节安排及内容提要…3

2.MSK信号的概念与理论研究5

2.1 MSK信号概述…5

2.2 MSK 信号的相位路径网络图6

2.3 MSK 信号与FSK、QPSK信号的对比（优劣）9

2.4 MSK 信号的信号特点…10

3. MSK 信号调制与解调方法与基本原理12

3.1 MSK 信号调制12

3.1.1 MSK 信号正交调制…12

3.1.2 MSK 信号正交相位调制…13

3.1.3 MSK 信号相位叠加法14

3.2 MSK 信号解调16

3.2.1 MSK 信号延时相干解调…16

3.2.2 MSK 信号相干解调延时判决…18

3.2.3 基于DFT的MSK 信号解调20

4.基于MATLAB的MSK信号的调制解调23

4.1 MATLAB软件概述…23

4.2调制算法实现23

4.2.1正交调制…23

4.2.2 相位调制…25

4.2.3相位叠加…27

4.3解调算法实现29

4.3.1延时相干解调…29

4.3.2相干解调延时判决…32

4.3.3 基于DFT的解调算法34

5.各种解调算法的性能分析36

5.1解调算法的性能分析…36

5.2解调算法的性能比较…39

结论41

致谢42

参考文献43

1 引言 MSK调制解调算法研究与实现:http://www.chuibin.com/tongxin/lunwen_205971.html