中波调幅广播传输系统方案

1、实验报告通信系统仿真题目：中波调幅广播传输系统:XXX学号：XXX题目：试对中波调幅广播传输系统进行仿真：(1) 基带信号：音频，幅度自行设定，基带测试信号频率在1006000Hz 可调。(2) 载波：初始相位为0,频率为5501605KHz可调。(3) 接收机选频滤波器带宽为12KHz,中心频率为lOOOKHzo(4) 在信道中加入噪声，要求计算信道中应该如入噪声的方差，并能够在 不同输入信噪比条件下，仿真测量包络检波解调和同步相干解调对调幅波的解调 输出信噪比。评分标准：1、包络检波解调方式实现解调；(20)2、同步相干解调方式实现解调；(20)3、封装解调输出信噪比子系统；(20)4、比

2、较2种解调方式的解调信号波形；(10)5、将2种解调方式在不同输入信噪比条件下的解调输出信噪比存入 Mat lab X作空间中，对比输出信噪比；(10)6、程序注释清晰，仿真曲线区别清晰。(10)7、结论分析。(10)一、程序代码(包括注释)：页脚Editor C:UscnAdm iri5tratorDc5ktopyunanb0oluol.mx file dit Text 0 ell TqqIs Debug Qcktop Window HdpID 3 id* 町 0黑珞耳|feJ樹対強iritill Stack Base -| fii 田(L S (?B昌瑁I 1.0+1.1Xclc: cle

3、ar: SHR_in_dS=-7:2:26:朋制度N佶号功豕N走玄为空矩隔SHR_in=10. * SnR_in_dB/10) :佶适ISW比Ji_a=0.3:P=0.5+(nca*2)/4:SHRdejiod=:10 - it -12 -13 -11 -15 -16 -17 -J for k=l: lengthi.SNR_in) sigaa2=P/SnR_in(kJ . ut(J sunshengxue ndlJ); ju n=size i.SIR_out);SHRdenodCk, :)=SNK_ont (n,:)上记录仿頁结宰 end plot ibc52.参数设置抽样时间终止时间(1)总

4、模型基带信号Signal GeneratorOutput various wave for as:Y(t) = Amp询ayefonn(Freq t)sm&T lme (t):Units:Vave form;Amplitude:Frequency;960Y)Interpret vector paraaeters as 1-D 毎丘皿泌噥厂 载波 Source Block Parameters; S-ignal Generator!Signal GeneratorOutput various wave forms:Y(t) = AjnptWaveform(Fre(L t)ParametersVa

5、ve form; sineTime (t): Use siaulat ion tineAmplitude:0.6Frequency:QK Caned | 噪声Mean;Variance:Pendom NumberSeed:Sample tijne:6.23e-8Saturation 模块Upper Liini-t:infLower Limi-t:0I Treat as gain when LinearizingE Enable zero-crossing: detection.Sample time (-1 for inherited):-1低通滤波器Passband edge frequen

6、cy (rad/s):2*pi*6e3工作站H Sink Block Parameters: To WorkspaceTo V/orkspaceWrite input to specified array or structure in a workspace. For menu based simulation data is wr it ten in the MATLAB base workspace Data is not availaLle until the siniulation is stopped, or paused. For command line simulation

7、using: sim coiruriand the workspace is specified using DstWorkspace field in the option structure.Paramet ersVariable nme;Limit data points to Last:infDecimation:Sample t ime (-1 for inherited):OKCancelHelpApply(2)子程序模型带阻滤波器Design method: ButterworthFilter type: BandstopFilter order:Lower passband e

8、dge frequency (rad,/s):2*pi*(le3-100)Upper passband edge frequency (rad/s):2*pi*(le34-100)带通滤波器页脚Design method: Butterworth Zero-OrderHoldLower passband edge frequency (rad,/s):2*pi*(le100)Upper passband edge frequency (rad/s):2*pi*(le34-100)Zero-Order Hold 模块Zero-order holdParametersSample time (-1

9、 for in?623e - 8 Buffer模块屯 Function Block Parameters! Bufferll dB conversion 模块Parajnet ersfcn函数fcr)1函数-1Expression:u一uSample time (-1 for inherited):三、仿真结果:Display示波器Time_Qffset_0_142.591145.031Displayk %-1 50-10-10-5051015202530输入信噪比dB403020OName田田田田田田田田田田田SNRjn.dBSNR outtoutValueMinMax0.52250.52250.52250.1259794.3.-929INaN,NaN;9.9120,9.NaNNaN20x2 doubles-5.44.45.03.2020203330.30000.30000.3000222&.5779e-046.577.6.577.1000x1 doubles0.01990.0200四、结果分析：从图中可见，高输入信噪比情况下，相干解调方法下的输出解调信噪比大致比包络检波 法好3dB左右，