基于MATLAB的信号调制与解调

目录第一章绪论.....................................................................................................................................11.1背景以及意义....................................................................................................................11.2发展前景............................................................................................................................1第二章信号的原理以及特点.......................................................................................................42.1噪声模型............................................................................................................................42.1.1噪声的分类.............................................................................................................42.1.2本文噪声模型.........................................................................................................42.2通用调制模型....................................................................................................................52.3AM信号的调制原理.........................................................................................................62.3.1AM信号数字模型以及特点...................................................................................62.3.2AM信号的波形和频谱特性...................................................................................6第三章信号的解调原理以及特点...............................................................................................83.1AM信号的解调原理及方式..............................................................................................83.2AM信号的相干解调...................................................................................................83.3AM信号的非相干解调...............................................................................................83.4抗噪声性能的分析模型..................................................................................................93.5相干解调的抗噪声性能................................................................................................93.6非相干解调的抗噪声性能..............................................................................................113.6.1大信噪比的情况...................................................................................................113.6.2小信噪比情况.......................................................................................................12第四章仿真结果及结论...............................................................................................................13参考文献（References）..............................................................................................................18附录..............................................................................................................................................19I基于MATLAB的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，MATLABIIModulationanddemodulationofsignalbasedonMATLABAbstract: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,giventhedifferentcircumstancesofthedemodulationsignaltonoiseratioc