基于MATLAB的扩频通信系统仿真毕业论文(2)

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 ........................................................................................................................... 6 3.SIMULINK模型建立 ..................................................................................................................... 8

3.1 随机整数发生器（Random Integer genarator） ....................................................... 8 3.2 PN序列发生器（PN Sequence Generator） ................................................................ 8 3.3 最小相移键控调制（M-PSK Modulator Passband） ................................................... 9 3.4 加性高斯白噪声信道（AWGN Channel） ....................................................................... 9 3.5 最小相移键控解调 （M-PSK Demodulator Passband） ........................................... 10 3.6 误码率分析仪（Error Rate Calculation） ............................................................. 10 3.7 其他设置 ......................................................................................................................... 12

3.7.1 RELAY 的设置 ..................................................................................................... 12 3.7.2 product的设置 .................................................................................................. 13 3.7.3 display 的设置 ................................................................................................. 13 3.7.4 频谱分析仪（spectrum scope）的设置 ......................................................... 13

4.仿真结果与分析 ......................................................................................................................... 15

4.1 Simulink仿真结果 .......................................................................................................... 15 4.2 Simulink仿真结果分析 ................................................................................................... 15 4.3 m文件的仿真结果 ........................................................................................................ 16 4.4 m文件的仿真结果分析 ................................................................................................ 16 5.结论 ............................................................................................................................................ 17 致谢 ................................................................................................................................................ 18 参考文献......................................................................................................................................... 19 附录 ................................................................................................................................................ 20

1.绪论 1.1 扩展频谱简介

扩展频谱通信具有很强的抗干扰性能，其多址能力、保密、抗多径等功能也倍受人们的关注，被广泛地应用于军事通信和民用通信中。扩频通信系统利用了扩展频谱技术，将信号扩展到很宽的频带上，在接收端对扩频信号进行相关处理即带宽压缩，恢复成窄带信号。对干扰信号而言，由于与扩频信号不相关，则被扩展到一个很宽的频带上，使之进入信号通频带内的干扰功率大大降低，相应增加了相关器输出端的信号/干扰比，对大多数人为干扰而言，扩频通信系统都具有很强的对抗能力。本文利用MATLAB对扩频系统中的m序列的产生、频谱、相关函数，以及整个扩频系统工作原理进行了仿真，为今后扩频通信系统在各个领域的应用和研究提供了依据。 1.2 扩展频谱技术特点

由于扩频通信能大大扩展信号的频谱，发端用扩频码序列进行扩频调制，以及在收端用相关 …… 此处隐藏：4077字，全部文档内容请下载后查看。喜欢就下载吧 ……