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：年月武汉理工大学《AM信号的仿真分析》Ⅰ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武汉理工大学《AM信号的仿真分析》ⅡModulationanddemodulationofAMsignalbasedonMATLABAbstract:Societybecomesmoredevelopednow,scienceandtechnologyintheupdate,inwhichsignalandanalogcircuitsoftenusedinmodulationanddemodulation,andAMmodulationanddemodulationisthemostbasic,isalsofrequentlyused.Toparticipateintheidentificationofsuchartificialmethods,therulingincludessubjectivefactors,willvaryfrompersontoperson,canidentifythetypeofmodulationisverylimited.Automaticmodulationrecognitiontechnologycanbeovercomenotonlytoparticipateinrecognitionofartificialdifficulties,andthecenterfrequencyandbandwidthoftheestimationerror,adjacentchannelcrosstalk,noiseandinterferencefactorssuchasthedeclineofeffectisrelativelyrobust.UsingAMmodulationanddemodulationcircuitwhichcanachievealotoffeatures,creatingalotofusefulandaffordableelectronicproducts,inordertofacilitateourlives.UsedinourdailylivesistheuseofAMradiomodulation,butalsointhefieldofmilitaryandcivilianresearchtopicsareveryimportant.ThemaincontentofthispaperistounderstandthemathematicalmodeloftheAMsignalandthemodulationandthedemodulationmethod.Demodulationdifferentmethodsindifferentcircumstancesofthedemodulationsignaltonoiseratiotheresultsofmethodsthatbetter,tomakethecomparison.RequirementismorethandoublethesoundandtheAMsignalmodulationanddemodulation.AMmodulationfirststudyofitsfunctionandinreallifeuse.AMdemodulationfollowedbyresearch,aswellassomerelatedknowledge,aswellasthroughitsuseofcommunicationsmorein-depthunderstandingofit.AMsignalfromthetoneofthemathematicalmodelandthemodulationanddemodulationmethods,thetwo-toneAMsignaltodrawamathematicalmodelandtheblockdiagramofmodulationanddemodulationandmodulationanddemodulationwaveforms.MATLABprogramminglanguagetousetoachievethetwo-toneAMsignalmodulationanddemodulation,giventhedifferentcircumstancesofthedemodulationsignaltonoiseratiocomparedtheresults.Keyword:AMsignal,Modulation,Demodulation,Noiseratiosignal,MATLAB1目录1、课程设计内容与要求...............................................................................................................21.1课程设计内容..................................................................................................................21.2设计要求...........................................................................................................................22、调制和解调原理.......................................................................................................................32.1调制与解调.......................................................................................................................32.2幅度调制的原理..............................................................................................................33．相干解调与包络检波...............................................................................................................43.1相干解调...........................................................................................................................43.2包络检波..........................................................................................................................44．噪声与抗噪声性能模型分析...................................................................................................64.1噪声的分类......................................................................................................................64.2本文噪声模型..................................................................................................................64.3抗噪声性能的分析模型..................................................................................................64.4相干解调的抗噪声性能................................................................................................75．AM基于matlab的调制与解调...............................................................................................95.1载波频率为30KＨz的载波信号....................................................................................95.2频率为300Hz的正弦波调制..........................................................................................95.2.1调制信号幅度=0.8×载波幅度...........................................................................105.2.2调制信号幅度=载波幅度时的调制信号............................................................115.2.3调制信号幅度=1.5×载波幅度时的调制信号...................................................125.3频率为300Hz的正弦波解调与输入输出信噪比曲线...................