AM信号的仿真分析

课程设计任务书

学生姓名：专业班级：

指导教师: 工作单位：

题目：AM信号的仿真分析

初始条件：

1）Matlab 软件

2）通信原理基础知识

设计内容和要求：

调制信号：分别为300Hz正弦信号和矩形信号；载波频率：30kHz；解调方式：分别为包络解调和同步解调；

要求：画出以下三种情况下调制信号、已调信号、解调信号的波形、频谱以及解调器输入输出信噪比的关系曲线；

1）调制信号幅度=0.8×载波幅度；2）调制信号幅度=载波幅度；

3）调制信号幅度=1.5×载波幅度；

指导教师签名：年月日

系主任（或责任教师）签名：年月

基于MATLAB的AM信号的调制与解调

摘要：现在的社会越来越发达，科学技术不断的在更新，在信号和模拟电路里面经常要用到调制与解调，而AM的调制与解调是最基本的，也是经常用到的。用AM调制与解调可以在电路里面实现很多功能，制造出很多有用又实惠的电子产品，为我们的生活带来便利。在我们日常生活中用的收音机也是采用了AM调制方式，而且在军事和民用领域都有十分重要的研究课题。

本文主要的研究内容是了解AM信号的数学模型及调制方式以及其解调的方法。不同的解调方法在不同的信噪比情况下的解调结果，那种方法更好，作出比较。要求是进行双音及以上的AM信号的调制与解调。先从AM的调制研究，研究它的功能及在现实生活中的运用。其次研究AM的解调，以及一些有关的知识点，以及通过它在通信方面的运用更加深入的了解它。从单音AM信号的数学模型及调制解调方式出发，得出双音AM信号的数学模型及其调制与解调的框图和调制解调波形。利用MATLAB编程语言实现对双音AM 信号的调制与解调，给出不同信噪比情况下的解调结果对比。

关键词：AM信号，调制，解调，信噪比，MATLAB

Modulation and demodulation of AM signal

based on MATLAB

Abstract: Society becomes more developed now, science and technology in the update, in which signal and analog circuits often used in modulation and demodulation, and AM modulation and demodulation is the most basic, is also frequently used. To participate in the identification of such artificial methods, the ruling includes subjective factors, will vary from person to person, can identify the type of modulation is very limited. Automatic modulation recognition technology can be overcome not only to participate in recognition of artificial difficulties, and the center frequency and bandwidth of the estimation error, adjacent channel crosstalk, noise and interference factors such as the decline of effect is relatively robust. Using AM modulation and demodulation circuit which can achieve a lot of features, creating a lot of useful and affordable electronic products, in order to facilitate our lives. Used in our daily lives is the use of AM radio modulation, but also in the field of military and civilian research topics are very important.

The main content of this paper is to understand the mathematical model of the AM signal and the modulation and the demodulation method. Demodulation different methods in different circumstances of the demodulation signal to noise ratio the results of methods that better, to make the comparison. Requirement is more than double the sound and the AM signal modulation and demodulation. AM modulation first study of its function and in real life use. AM demodulation followed by research, as well as some related knowledge, as well as through its use of communications more in-depth understanding of it. AM signal from the tone of the mathematical model and the modulation and demodulation methods, the two-tone AM signal to draw a mathematical model and the block diagram of modulation and demodulation and modulation and demodulation waveforms. MATLAB programming language to use to achieve the two-tone AM signal modulation and demodulation, given the different circumstances of the demodulation signal to noise ratio compared the results.

Keyword: AM signal, Modulation, Demodulation, Noise ratio signal, MATLAB