摘 要
在通信技术的发展中,通信系统的仿真技术是一个技术重点。本文将着重讨论模拟通信系统中的调制解
调系统的基本原理以及抗噪声性能,并在 MATLAB 软件平台上仿真实现几种常见的模拟调制方式。最
常用最重要的模拟调制方式是用正弦波作为载波的幅度调制和角度调制。常见的调幅(AM)、双边带
(DSB)、残留边带( VSB)和单边带(SSB)等调制就是幅度调制的几个典型实例;而频率调制
(FM)就是角度调制中被广泛采用的一种。在线性调制系统中,文中将以调幅( AM)、双边带
(DSB)和单边带(SSB)为说明对象,从原理等方面进行分析阐述并进行仿真分析;而在非线性调制
中,以常用的调频(FM)和调相(PM)为说明对象,说明其调制原理,并进行举例仿真分析。利用
MATLAB 对模拟调制系统进行仿真,将结合 MATALB 模块和 Simulink 工具箱的实现,并对仿真结果进
行分析,从而更深入地掌握模拟调制系统的相关知识。
关键词 MATLAB 模拟通信系统 调制解调 仿真 频谱分析 信噪比
Title Based on MATLAB analog modulation system simulation
Abstract
In the development of communication technology, communication system simulation technology is a technical
focus. This paper will focus on simulation of communication systems in the modem system and the basic
principles of anti-noise performance and MATLAB simulation software platform to achieve some common
analog modulation. The most important of the most commonly used analog modulation is the sine wave as a
carrier perspective modulation and amplitude modulation. Common AM (AM), with bilateral (DSB), residual
sideband (VSB) and single sideband (SSB) modulation, and so is the amplitude modulation of a few typical
examples, and frequency modulation (FM) modulation in the point of view is widely used. Modulation of the
online system, the text will be AM (AM), with bilateral (DSB) and single sideband (SSB) for that object, from
the basic principles, and other aspects of analysis and simulation analysis on while in nonlinear Modulation, as
commonly used FM (FM) and Phase Modulation (PM) for that target on its modulation principle, for example
simulation and analysis. MATLAB simulation of the modulation system simulation, will combine MATALB
model block and Simulink toolbox the realization of the analysis and simulation results, thus better grasp of the
analog modulation system knowledge.
Key Words MATLAB simulation of communication systems modem simulation spectrum analysis SNR
一、
利用 MATLAB 软件仿真 PM 通信系统。
设消息信号为:
其中 t0=0.1。用这 个消息信号调制载波 c(t)=cos(2πfct),fc=250Hz,偏离常数 Kf=100。
(1)在时域和频域中画出已调信号。
(2)将解调器输出与原消息信号进行比较。
(3)若 t0=0.15s,偏离常数 Kf=50,fc=200Hz。
再做(1)、( 2)小题。
二、
程序清单:
function c=fm
echo on
t0=0.2;
% signal duration
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