毕业论文
基于MATLAB的扩频通信系统仿真
基于MATLAB的扩频通信系统仿真
摘 要
本文阐述了扩展频谱通信技术的理论基础和实现方法，利用MATLAB提供的可视化工具SIMULINK建立了扩频通信系统仿真模型，详细讲述了各模块的设计，并指出了仿真建模中要注意的问题。在给定仿真条件下，运行了仿真程序，得到了预期的仿真结果。同时，利用建立的仿真系统，研究了扩频增益与输出端信噪比的关系，结果表明，在相同误码率下，增大扩频增益，可以提高系统输出端的信噪比，从而提高通信系统的抗干扰能力。
关键词 扩频通信, 信噪比， 误码率
Simulation of the Spread Spectrum Communication System Based
on MATLAB
Author: Guo Jian Tutor: Tang Hailing
Abstract
The theory base and realizing methods of the spread spectrum communication technology was presented in this study. The simulation model of the spread spectrum communication system was built by using SIMULINK, which is provided by MATLAB. In addition, each module of the simulation model was introduced in detail，and pointed out the problems that must be pay attention to in the system simulation. On the basis of the designed simulation conditions, the simulation program was run and the anticipant results were gained. Moreover, the relationship between the spread spectrum gain and the fan-out error rate was also studied by use of the simulation system. The results showed that on the base of the same error rate, if the spread spectrum gain was enlarged, the Signal-to-Noise of the system fan-out would be enhanced and the anti-jamming capability of the communication system would also be enhanced.
Keywords: spread spectrum communication, Signal-to-Noise, error rate
目录
1.绪论 .............................................................................................................................................. 1
1.1 扩展频谱简介 ................................................................................................................... 1 1.2 扩展频谱技术特点 ........................................................................................................... 1 1.3 研究扩频通信的目的和意义 ......................................................................................... 2 1.4 本文的主要内容 ............................................................................................................... 2 2.扩展频谱技术 ............................................................................................................................... 3
2.1 理论基础 ........................................................................................................................... 3 2.2 频谱的扩展实现 ............................................................................................................... 4 2.3 m序列 ................................................................................................................................ 5 2.5 本章小结 ........................................................................................................................... 8 3.SIMULINK模型建立 ..................................................................................................................... 9
3.1 随机整数发生器（Random Integer genarator） ....................................................... 9 3.2 PN序列发生器（PN Sequence Generator） .............................................................. 10 3.3 最小相移键控调制（M-PSK Modulator Passband） ................................................. 11 3.4 加性高斯白噪声信道（AWGN Channel） ..................................................................... 11 3.5 最小相移键控解调 （M-PSK Demodulator Passband） ........................................... 12 3.6 误码率分析仪（Error Rate Calculation） ............................................................. 12 3.7 其他设置 ......................................................................................................................... 13
3.7.1 RELAY 的设置 ..................................................................................................... 13 3.7.2 product的设置 .................................................................................................. 14 3.7.3 display 的设置 ................................................................................................. 14 3.7.4 频谱分析仪（spectrum scope）的设置 ......................................................... 14
4.仿真结果与分析 ......................................................................................................................... 16
4.1 Simulink仿真结果 .......................................................................................................... 16 4.2 Simulink仿真结果分析 ................................................................................................... 18 4.3 m文件的仿真结果 ........................................................................................................ 19 4.4 m文件的仿真结果分析 ................................................................................................ 20 5.结论 ............................................................................................................................................ 21 致谢 ................................................................................................................................................ 22 参考文献......................................................................................................................................... 23 附录 ................................................................................................................................................ 24