直接序列扩频通信系统的设计

直接序列扩频通信系统的设计(任务书,开题报告,论文17000字)
摘要
本文是对直接序列扩频通信系统进行设计并采用MATLAB进行仿真。直接序列扩频通信系统就是直接用具有高码率的扩频码序列在发送端扩展信源信号的频谱。而在接收端，用与发送端完全相同的扩频码序列再去进行解扩，把展宽后的扩频信号还原成原始信息的一种信息传输方式。直接序列扩频通信技术目前在军事通信及无线局域网等领域具有广泛应用。本文通过在Simulink中搭建设计的直接序列扩频通信系统，设置各个模块的参数，使得该系统可以正常传输信息，观察信息从信源发出到接收端接收到信号的整个传输过程，用示波器观察信号经过每一个模块之后的波形变化情况以及用频谱仪观察信号经过每个模块后的信号频谱变化过程，同时在该系统中加入单频干扰信号，以此来测试直接序列扩频通信系统的抗干扰性能。通过对整个系统的通信测试和抗干扰测试，证明直接序列扩频通信系统是一种很可靠的通信系统。
关键词：直接序列；扩频通信；抗干扰

Abstract
This paper designs and simulates the direct sequence spread spectrum communication system based on the simulation module of Simulink library in MATLAB. Direct sequence spread spectrum communication system is to extend the spectrum of the source signal at the sending end by directly using the spread spectrum sequence with high code rate. At the receiving end, the spread spectrum signal is reduced to the original information by using the identical spread spectrum sequence. Direct sequence spread spectrum communication technology is widely used in military tactical communication and wireless LAN. Based on Simulink in the building design of direct sequence spread spectrum communication system, set the parameters of the various modules, allowing the system to normal transport information, observe the information from the source to the receiver in the received signal to the whole transmission process, using the oscilloscope observation signal waveform change after each module and using spectrometer observation signal into the process of the change of signal spectrum after each module, add single frequency interference signal in the system at the same time, in order to test the anti-interference performance of direct sequence spread spectrum communication system. Through the communication test and anti-interference test of the whole system, it is proved that direct sequence spread spectrum communication system is a reliable communication system.
Key words: direct sequence；spread spectrum；communication anti-interference

目录
第1章绪论    1
1.1课题背景    1
1.2 直接序列扩频通信系统的发展    1
1.3 直接序列扩频通信系统的特点    2
1.4 直接序列扩频通信系统的意义    3
1.5本文结构安排    4
第2章直接序列扩频通信系统原理    5
2.1扩频通信的概念    5
2.2扩频通信工作原理    5
2.3扩频伪随机序列    6
2.3.1 m序列    6
2.3.2 Gold码序列    7
2.4扩频通信的分类    7
2.5扩频通信的特点    8
2.6扩频通信的使用范围    9
2.7直接序列扩频通信的概念    10
2.8直接序列扩频通信系统的工作原理    11
2.9直接序列扩频通信系统的性能分析    12
2.9.1直接序列扩频通信系统的抗干扰性    12
2.9.2直接序列扩频通信系统的抗多径效应性能分析    14
2.10直接序列扩频通信系统的实现方法    14
2.10.1扩频调制    15
2.10.2载波调制    15
第3章直接序列扩频通信系统的仿真实现    16
3.1直接序列扩频通信系统的框图    16
3. 2直接序列扩频通信系统发射机的设计    16
3.3编码信道的设计    21
3.4直接序列扩频通信系统接收端的设计    22
第4章直接序列扩频通信系统的抗干扰性能分析    25
4.1抗干扰的理论基础    25
4.2抗干扰的仿真研究    26
结论    32
参考文献    33
致谢    34