基于MATLABSimulink的模拟通信系统的仿真(非线性调制).docx

32基于MATLAB/Simulink的模拟通信系统的仿真（非线性调制）白雨轩（陕西理工学院物理与电信工程学院通信1104班陕西汉中723003）指导老师：侯宝生【摘要】模拟通信系统的非线性调制包括调频和调相即角度调制。角度调制与线性调制不同已调信号频谱不再是原调制信号频谱的线性搬移而是频谱的非线性变换会产生与频谱搬移不同的新的频率成分。FM广泛应用于高保真音乐广播、电视伴音信号的传输、卫星通信和蜂窝电话系统等.PM除直接用于传输外也常用做间接产生调频信号的过渡。调频和调相之间关系密切。本设计利用MATLAB在其中利用simulink工具箱和M文件编写程序的功能来实现FM和PM的调制与解调过程并分别绘制出基带信号载波信号已调信号的时域波形；再进一步分别绘制出对已调信号叠加噪声后信号相干解调后信号和解调基带信号的时域波形；并通过与理论结果波形对比来分析该仿真调制与解调系统的正确性及噪声对信号解调的影响。在MATLANB7.8.0中完成了对FM和PM的调制和解调以及对叠加噪声后解调结果的观察。通过该课程设计达到了实现FM和PM信号通过信道调制和解调系统的仿真目的。【关键字】通信系统FMPM调制解调M文件simulinkFMsignalmodulationanddemodulation[Abstract]Thenonlinearmodulationanalogcommunicationsystemincludingthefrequencymodulationandphasemodulationanglemodulation.Anglemodulationandlinearmodulationthemodulatedsignalspectrumisnolongerlinearmovementoftheoriginalmodulationsignalspectrumnonlineartransformationbutthespectrumcanproducenewcomponentsofdifferentfrequenciesandfrequencyspectrumshift.FMiswidelyusedinhighfidelitymusicbroadcastingtelevisionsoundsignaltransmissionsatellitecommunicationandcellulartelephonesystemfor.PMinadditiontothedirecttransmissionalsousedastransitionindirectFMsignal.CloserelationshipbetweenFMandpm.ThisdesignusingMATLABinwhichtheprogramusingSimulinktoolboxandMfiletorealizethefunctionofmodulationanddemodulationprocessofFMandPMrespectivelyanddrawthebasebandsignalthecarriersignalthemodulatedwaveformsignal;furtherweredrawnonthemodulatedsignalissuperimposednoisesignalthetimedomainwaveformcoherentdemodulationafterthesignalanddemodulationofbasebandsignal;andthroughthetheoreticalresultsandwaveformcomparisontoanalyzetheimpactofthesimulationaccuracyandnoisemodulationanddemodulationsystemforsignaldemodulation.ThemodulationanddemodulationofFMandPMandobservedafteraddingnoisedemodulationresultsinMATLANB7.8.0.ThroughthecurriculumdesigntoachievetheFMandPM