基于Simulink的通信系统仿真

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摘 要

随着科学技术的发展，计算机仿真技术呈现出越来越强大的活力，它大大节省了人力、物力和时间成本，在当今教学、科研、生产等各个领域发挥着巨大的作用。使用MATLAB和SIMULINK作为辅助教学软件，一方面可以摆脱繁杂的大规模计算；另一方面还可以使学生有机会自己动手构建模型，所花费的代价要远小于实际建模。Simulink是Mathworks公司推出的基于Matlab平台的著名仿真环境Simulink作为一种专业和功能强大且操作简单的仿真工具，目前已被越来越多的工程技术人员所青睐，它搭建积木式的建模仿真方式既简单又直观，而且已经在各个领域得到了广泛的应用。

本文主要探究数字频带通信系统的各种传输方式的优良特性，分别为ASK、FSK、PSK、QPSK几种基本但是非常重要的方式，并通过使用MATLAB中SIMULINK功能对各种方式进行仿真，展示数字通信系统的工作过程，最后通过数字信号的分析可以得出各种数字通信方式的误码率，并且分析得出QPSK为最佳的传输方式。主要由于QPSK信号的相位是四个正交的点，这样相对别的方式拥有最好的欧氏距离，也就是说抗干扰能力最强，而且QPSK信号产生非常简单，所以QPSK在日常数字传输中得到广泛应用。

关键字:数字通信系统,Matlab,ASK,FSK,PSK,仿真.

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Abstract

With the development of science and technology, computer simulation technology becomes more and more powerful vitality, it saves the manpower, material resources and time , it plays an important role in the teaching, scientific research, production and other fields. MATLAB with its powerful function in simulation software in many science and engineering talent showing itself, it becomes the most popular international computing software tools. MATLAB not only has strong function and easy operation, the user can concentrates on the research questions, and it doesn't need to spend too much time on programming. MATLAB and SIMULINK are used as the auxiliary teaching software, one can get rid of the large-scale complicated computation; on the other hand, also can make the students have the opportunity to do-it-yourself model construction, the cost to be far less than the actual modeling. Simulink is Mathworks's famous Simulink simulation environment based on Matlab platform as a professional and functional simulation tool with powerful and simple operation, it has been favored by more and more engineering and technical personnel, it builds the modeling method building is simple and intuitive, and has been in various fields has been widely applied.

The excellent properties of various transmission methods this paper mainly research on digital band communication system, respectively ASK, FSK, PSK, QPSK several basic but very important, and by using the SIMULINK function in MATLAB of various simulation, to show the reader the work process of digital communication system, finally, through the analysis of digital signal can be obtained. Rate of various digital communication mode, and analysis of the transmission mode of QPSK the best. Mainly due to the phase of the QPSK signal is four orthogonal, so relative to other ways to have the best Euclidean distance, that is to say the anti-interference ability is the strongest, and the QPSK signal generation is very simple, so

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QPSK has been widely used in the daily digital transmission.

Key words: digital communication system, Matlab, ASK, FSK, PSK, simulation.

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目录

1 前言 ............................................................ 1

1.1 选题的意义和目的 ........................................... 1 1.2 国内外研究现状 ............................................. 2 1.3 通信系统及其仿真技术 ....................................... 4 1.4 毕设的主要内容 ............................................. 5 2 Simulink与通信系统仿真 .......................................... 6

2.1 通信系统仿真的研究方法和技术路线 ........................... 6

2.1.1 通信系统仿真的研究方法 ............................... 6 2.1.2 通信系统仿真的技术路线 ............................... 6

3 现代通信系统原理 ................................................ 7

3.1 通信系统的一般模型 ......................................... 7 3.2 数字通信系统模型 ........................................... 7 3.3 各种数字调制方式比较 ....................................... 8 4 数字通信系统的仿真原理及框图 ................................... 10

4.1 ASK信号的调制和解调原理及频谱分析 ......................... 11

4.1.1 ASK信号调制解调原理 ................................ 11 4.1.2 ASK信号的功率谱密度 ................................ 13 4.2 FSK信号调制解调原理及功率谱和抗噪声性能 ................... 15

4.2.1 FSK基本原理 ........................................ 15 4.2.2 FSK信号调制基本原理 ................................ 16 4.2.3 FSK信号的功率谱密度 ................................ 17

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