基于mat lab的数字调制系统仿真与分析本科论文 .doc

基于Mat lab的数字调制系统仿真与分析 摘 要 数字调制是通信系统中最为重要的环节之一，数字调制技术的改进也是通信系统性能提高的重要途径。本文首先分析了数字调制系统的五种基本调制解调方法，然后，运用Matlab及附带的图形仿真工具 ——Simulink设计了这几种数字调制方法的仿真模型。通过仿真，观察了调制解调过程中各环节时域和频域的波形，并结合这几种调制方法的调制原理，跟踪分析了各个环节对调制性能的影响及仿真模型的可靠性。最后，在仿真的基础上分析比较了各种调制方法的性能，并通过比较仿真模型与理论计算的性能，证明了仿真模型的可行性。关键词：数字调制；分析与仿真；Matlab；Simulink；GUI图形界面。In this paper, five usual methods of digital modulation are introduced firstly. Then their simulation models are built by using MATLAB’s simulation tool, SIMULINK. Through observing the results of simulation, the factors that affect the capability of the digital modulation system and the reliability of the simulation models are analyzed. And then, the capability of three digital modulation simulation models, 2-FSK, 2-DPSK and MSK, have been compared, as well as comparing the results of simulation and theory. Keywords:　Digital modulation; analysis; simulation; MATLAB; SIMULINK 1引言.......................................................1 1.1数字调制系统概述.......................................1 1.1.1数字通信系统的组成...................................1 1.1.2数字通信系统的特点...................................2 1.2数字调制的意义.........................................5 1.3 Matlab在通信系统仿真中的应用..........................6 2数字调制系统的相关原理.....................................7 2.1二进制幅度键控(2-ASK)..................................7 2.2二进制频移键控(2-FSK)..................................7 2.3二进制相移键控(2-PSK)..................................8 2.4多进制数字调制.........................................8 3数字调制系统的仿真设计.....................................9 3.1数字调制系统各个环节分析...............................9 3.1.1仿真框图...........................................10 3.1.2信号源仿真及参数设置...............................11 3.1.3调制与解调模块.....................................11 3.1.4信道...............................................12 3.2仿真模型的设计及结果分析...............................13 3.2.1 2-ASK..............................................13 3.2.2 2-FSK..............................................18 3.2.3 2-DPSK...............................