直接序列扩频系统设计毕业论文要点分析.doc

扩频通信技术实现方法的研究和设计 ——DS直接序列扩频 目 录 引言 3 1扩频通信系统1.1扩展频谱通信的定义1.2扩频通信的理论基础1.3扩频通信的主要性能指标 1.4扩频通信的主要特点频谱扩展的实现和直接序列扩频扩频系统需要满足以下几个条件扩频通信特征直序扩频通信系统2.1直序扩频通信系统框图2.2直接序列扩频信号的产生原理2.3直接序列扩频原理直接序列扩频信号的实现方法用编程来实现直序扩频通信系统3.1直接序列扩频3.2信号解调3.3差错概率 Monte Carlo仿真 SIMULINK仿真1直扩程序M-文件 40 附录2直扩-SIMLINK动态仿真模框图 摘 要 扩频通信技术(简称扩频通信)是一种新兴的高科技通信技术，具有大容量、抗干扰、低截获功率等特点以及可实现码分多址(CDMA)等优点，在军事和民用通信系统中都得到了广泛的应用，并成为下一代移动通信的技术基础。在扩频通信系统中，直序扩频的应用最为广泛。首先介绍扩频通信的基本原理及组成，重点论述了直序扩频通信在通信系统中的使用。MATLAB因具有强大的数学计算、算法推导、建模仿真和图形绘制等功能而广泛应用于各领域，本文利用MATLAB的M语言进行编程、仿真，从而对CDMA无线通信系统的性能进行了分析。在此基础上，通过实例介绍了建立系统仿真模型的方法。利用MATLAB软件对CDMA无线通信系统的性能进行了分析。可见利用MATLAB/SIMULINK进行系统仿真简单、方便、形象、具体，是系统仿真较好软件之一。 MATLAB； 干扰 Abstract Spread spectrum communication is a sort of new high-tech communication technique, it has a number of internal advantages, such as large capacity, interference immunity, low probability of intercept, code division multiple access(CDMA)etc ,which make it get broad applications in civilian as well as military environments ,and become the technical groundwork of next generation mobile communications, Direct sequencing spread-spectrum was widely used. This paper introduces fundamental and constitutes of spectrum communication.Second it emphasizes elaborating spread-spectrum’s technique in the application of system. MATLAB has been using in a variety of fields as its powerful and universal functions on mathematics calculation, algorithm interference , modeling and simulation, graphic structure, etc, we are making use of MATLAB’s M language to design program and to make simulation on error rate performance and then to analyze the performance on CDMA wireless communication system . On this basis, the method to build system simulation model is introduced with a simple example. Meanwhile a spreading-spectrum communication system is built to simulate it and prove its validity. Obviously, to simulate with MATLAB/SIMULINK is simple, convenient, visualized, sp