MATLAB仿真的ASKPSKFSK性能比较和分析报告

1、2ASK、 2FSK、 2PSK 数字调制系统的Matlab 实现及性能分析与比较引言：数字带通传输系统为了进行长距离传输，克服传输失真，传输损耗，同时 保证带内特性。必须对数字信号进行载波调制，将信号频谱搬移到高频段才能在 信道中传输，因而现代通信系统采取数字调制技术。通过数字基带信号对载波某 些参量进行控制，使之随机带信号的变化而变化。根据控制载波参量大的不同， 数字调制有调幅（ASK，调频（FSK），调相（PSK）三种基本形式。Matlab用于仿 真，分析和修改，还可以应用图形界面功能 GUI能为仿真系统生成一个人机交互 界面，便于仿真系统的操作，因此采用 matlab对数字系统进行仿真

2、。通过对系 统的仿真，我们可以更加直观的了解数字调制系统的性能 （）及影响性能的因素， 从而便于改进系统，获得更佳的传输性能。关键词： 数字系统性能 ASK. FSK. PSK. Matlab.仿真.数字调制与解调原理1.1 2ASK(1)2ASK2ASK就是把频率、相位作为常量，而把振幅作为变量，信息比特是通过载波的 幅度来传递的。由于调制信号只有0或1两个电平，相乘的结果相当于将载频或 者关断，或者接通，它的实际意义是当调制的数字信号 1时，传输载波；当调 制的数字信号为0时，不传输载波。公式为：Aco ct,当 ak = 1 皿帖。当ar抽样脉冲COSWT1.2 2FSK2FSK可以看做

3、是2个不同频率的2ASK勺叠加，其调制与解调方法与 2ASK差不多，主要频率F1和F2,不同的组合产生所要求的2FSK调制信号3FSKJWiflHeffl公式如下：Acosjt,当 ak = 1 S2FSK(t Acos 2t，当a/01.3 2PSK2PSK以载波的相位变化为基准，载波的相位随数字基带序列信号的 1或者0而 改变，通常用已经调制完的载波的 0或者n表示数据1或者0,每种相位与之一一对应2尸 I弋近J牛U框两覩宇丢帶梧号蒂刈迎菠莖2PSK信号的解遍框图抽悴判决垃定时1S复強岀信号二.数字调制技术的仿真实现本课程设计需要借助 MATLAB勺M文件编程功能，对2ASK.2PSK.2

4、FSK进行调制 与解调的设计，并绘制出调制与解调后的波形，误码率的情况分析，软件仿真可 在已有平台上实现。1.2ASK代码主函数close allclear alln=16;fc=1OOOOOO; bitRate=1OOOOOO;N=50;%no ise=ti;no ise=10;sig na匸source( n,N); %生成二进制代码tran smittedSig na匸askModu(sig nal,bitRate,fc,N);%调制后信号sig nal1=gussia n(tra nsmittedSig nal, no ise); %加噪声con figueSig nal=demoAS

5、K(sig nal1,bitRate,fc ,n, N);source 代码fun cti onsen dSig na匸source( n,N)sendSignal=randint(1,n)bit=;for i=1:length(sendSignal)if sendSignal(i)=0 bit1=zeros(1,N);elsebit1=ones(1,N);endbit=bit,bit1;endfigure(1)plot(1:length(bit),bit),title( transmitting of binary axis(0,N*length(sendSignal),-2,2);enda

6、skModu 代码function transmittedSignal=askModu(signal,bitRate,fc,N)%signal号，bitrate 为bit速率，fc调制信号频率，N%signal=0 0 1 0 1 1 0 1; % bitRate=1000000;% fc=1000000; % N=32;t=linspace(0,1/bitRate,N); c=sin(2*pi*t*fc); transmittedSignal=;for i=1:length(signal) transmittedSignal=transmittedSignal,signal(i)*c;end

7、 figure(2) % 画调制图 plot(1:length(transmittedSignal),transmittedSignal);title( of ASK );grid on;figure(3)% 画频谱实部 m=0:length(transmittedSignal)-1; F=fft(transmittedSignal);plot(m,abs(real(F),title(ASK_frequency-domain analysis realgrid on;%figure(4) 画频谱虚部 %plot(m,imag(F);title(ASK_frequency-domain anal

8、ysis imag); %grid on;end),grid on ;为输入信Modulation);CheckRatePe 代码function PeWrong=CheckRatePe(signal1,signal2,s)rights=0;wrongs=0;for ki=1:s-2if (signal1(ki)=signal2(ki) rights=rights+1;elsewrongs=wrongs+1;endendPeWrong=wrongs/(wrongs+rights);enddemoASK 代码functionloadsignal1=receivedSignal;bitstream

9、=demoASK(receivedSignal,bitRate,fc,n,N)num%?d-%LPFu ? i 2 %?o 3ue ?signal2=abs(signal1); signal3=filter(num1,1,signal2);IN=fix(length(num1)/2);bitstream=;LL=fc/bitRate*N;i=IN+LL/2;while (i=0.5; i=i+LL;endfigure(6)subplot(3,1,1); %接收波形plot(1:length(signal1),signal1);title( terminal(including noise);g

10、ridsubplot(3,1,2);%接收整流后波形plot(1:length(signal2),signal2);title( subplot(3,1,3);%包络检波波形plot(1:length(signal3),signal3);title(bit=;for i=1:length(bitstream)if bitstream(i)=0 bit1=zeros(1,N);else%?D?Wave of receivingon;Wave of commutate );gridWave of LPF );grid onon;bit1=ones(1,N); end bit=bit,bit1;en

11、dfigure(7)% 解调后的二进制波形on ;plot(bit),title( binary of receiving terminal ),grid axis(0,N*length(bitstream),-2.5,2.5);endgussian 代码 %加高斯白噪声function signal=gussian(transmittedSignal,noise) signal=sqrt(2)*transmittedSignal; signal=awgn(signal,noise);figure(5)plot(1:length(signal),signal);title( Wave incl

12、uding noise ),gridon ;end/ fsk 主函数代码close allclear all n=16;% 二进制代码长度f1=18000000;% 频率 1f2=6000000;% 频率 2bitRate=1000000;%bit 速率N=50;% 码元宽度%noise=ti;调制加噪声解调noise=10;% 家性噪声大小 signal=source(n,N);% 产生二进制代码 transmittedSignal=fskModu(signal,bitRate,f1,f2,N);% signal1=gussian(transmittedSignal,noise);% con

13、figueSignal=demoFSK(signal1,bitRate,f1,f2,N);%source 代码 %二进制信号产生函数function sendSignal=source(n,N)sendSignal=randint(1,n)bit=;for i=1:length(sendSignal)if sendSignal(i)=0bit1=zeros(1,N);elsebit1=ones(1,N);endbit=bit,bit1;endfigure(1),grid on ;plot(bit),title( transmitting of binary axis(0,N*length(se

14、ndSignal),-2.5,2.5); endfskModu 代码 %频率调制函数function transmittedSignal=fskModu(signal,bitRate,f1,f2,N) t=linspace(0,1/bitRate,N);c1=sin(2*pi*t*f1);%调制信号 1c2=sin(2*pi*t*f2);%调制信号 2transmittedSignal=;for i=1:length(signal)% 调制 if signal(i)=1transmittedSignal=transmittedSignal,c1;else transmittedSignal=t

15、ransmittedSignal,c2;endendfigure(2) % 画调制后波形图Modulation);plot(1:length(transmittedSignal),transmittedSignal);title(of FSK );grid on; figure(3) % 画调制后频谱图 m=0:length(transmittedSignal)-1;F=fft(transmittedSignal); plot(m,abs(real(F),title( ASK_frequency-domain analysis real grid on;enddemoFSK 代码functio

16、n bitstream=demoFSK(receivedSignal,bitRate,f1,f2,N) load num signal1=receivedSignal;signal2=filter(gaotong,1,signal1);%通过 HPF ，得到高通分量signal3=abs(signal2); signal3=filter(lowpass,1,signal3);bitstream=;IN1=fix(length(lowpass)/2)+fix(length(gaotong)/2); 间流%通过低通，形成包络%延迟时%每个 bit的抽样点数%判决on;Wave of receivi

17、ngAfterPassingHPF);gridonAfterPassingLPF);gridonbitstream1=;LL=N;i=IN1 +LL/2;while (i=0.5; i=i+LL;endbitstream1figure(5)subplot(3,1,1);plot(1:length(signal1),signal1);title( terminal(including noise) );grid subplot(3,1,2);plot(1:length(signal2),signal2);title( subplot(3,1,3);plot(1:length(signal3),s

18、ignal3);title(signal4=filter(daitong,1,signal1); signal5=abs(signal4); signal5=filter(lowpass,1,signal5); IN2=fix(length(lowpass)/2)+fix(length(daitong)/2); bitstream2=;%每个 biton;AfterPassingBPF);gridonAfterPassingLPF);gridonWave of receivingLL=N;i=IN2 +LL/2;while (i=0.5; i=i+LL;endbitstream2figure(

19、6)subplot(3,1,1);plot(1:length(signal1),signal1);title( terminal(including noise) );grid subplot(3,1,2);plot(1:length(signal4),signal4);title( subplot(3,1,3);plot(1:length(signal5),signal5);title(%通过 BPF 得到低频分量流%通过 LPF ，形成包络%延迟时间的的抽样点数%判决%判决for i=1:min(length(bitstream1),length(bitstream2)if (bitstr

20、eam1(i)bitstream2(i)bitstream(i)=1;elsebitstream(i)=0;endendbitstreambit=;%接收端波形for i=1:length(bitstream)if bitstream(i)=0 bit1=zeros(1,N);elsebit1=ones(1,N);endbit=bit,bit1;endfigure(7)on ;plot(bit),title(binary of receiving terminal),gridaxis(0,N*length(bitstream),-2.5,2.5);endCheckRatePe 代码functi

21、on PeWrong=CheckRatePe(signal1,signal2,s) rights=0;wrongs=0;for ki=1:s-2if (signal1(ki)=signal2(ki) rights=rights+1;else wrongs=wrongs+1;endendPeWrong=wrongs/(wrongs+rights);endgussian 代码function signal=gussian(transmittedSignal,noise) signal=sqrt(2)*transmittedSignal; signal=awgn(signal,noise);figu

22、re(4)plot(1:length(signal),signal),title( Adding Noise );grid on;end2psk 主函数代码close allclear alln=16;% 二进制码长fc=1000000;% 载波频率bitRate=1000000; 信息频率N=50;% 码宽noise=10;% 信道加性噪声大小 signal=source(n,N); 生成二进制代码 transmittedSignal=bpskModu(signal,bitRate,fc,N); 分析对信号进行调制并进行频谱signal1=gussian(transmittedSignal,

23、noise)%加信道噪声configueSignal=demoBPSK(signal1,bitRate,fc,n,N);%信号解调source 代码function sendSignal=source(n,N)sendSignal=randint(1,n)bit=;for i=1:length(sendSignal)if sendSignal(i)=0bit1=zeros(1,N);elsebit1=ones(1,N);endbit=bit,bit1;endfigure(1)plot(bit),title( transmitting of binary axis(0,N*length(send

24、Signal),-2.5,2.5); end),grid on ;bpskModu 代码function transmittedSignal=bpskModu(signal,bitRate,fc,N) t=linspace(0,1/bitRate,N);c1=sin(2*pi*t*fc);c2=sin(2*pi*t*fc + pi);transmittedSignal=;for i=1:length(signal) if signal(i)=1 transmittedSignal=transmittedSignal,c1; elsetransmittedSignal=transmittedSi

25、gnal,c2;endModulationend figure(2) % 画调制图 plot(1:length(transmittedSignal),transmittedSignal);title( of BPSK );grid on;figure(3)% 画频谱图 m=0:length(transmittedSignal)-1; F=fft(transmittedSignal););plot(m,abs(real(F),title( BPSK_frequency-domain analysis real grid on;endCheckRatePe 代码function PeWrong=C

26、heckRatePe(signal1,signal2,s)rights=0;wrongs=0;for ki=1:s-2if (signal1(ki)=signal2(ki)rights=rights+1;elsewrongs=wrongs+1;endendPeWrong=wrongs/(wrongs+rights);enddemoBPSK 代码function bitstream=demoBPSK(receivedSignal,bitRate,fc,n,N) load num %读取 num 存储的低通滤波用的数据 signal1=receivedSignal;t=linspace(0,1/b

27、itRate,N);c=sin(2*pi*t*fc);signal=;for i=1:nsignal=signal,c;endsignal2=signal1.*signal;signal3=filter(num1,1,signal2);IN=fix(length(num1)/2);bitstream=;LL=fc/bitRate*N;i=IN+LL/2;while (i=0; i=i+LL;%乘同频同相 sin%LPF, 包络检波 3 %?延迟时间%判决endfigure(5)subplot(3,1,1);%画接收的包含噪声的波形plot(1:length(signal1),signal1);

28、title(terminal(including noise) );grid on; subplot(3,1,2);% 相干解调波形 plot(1:length(signal2),signal2);title(Fuction );grid on; subplot(3,1,3);% 包络检波波形 plot(1:length(signal3),signal3);title(Wave of receivingAfter Multipling sinWave of LPF);gridon;bit=;for i=1:length(bitstream)if bitstream(i)=0bit1=zeros

29、(1,N);elsebit1=ones(1,N);endbit=bit,bit1;endfigure(6) 二进制接收信号波形);grid on ;plot(bit);title( binary of receiving terminal axis(0,N*length(bitstream),-2.5,2.5);endgussian 代码function signal=gussian(transmittedSignal,noise) signal=sqrt(2)*transmittedSignal; signal=awgn(signal,noise);figure(4)plot(1:lengt

30、h(signal),signal),grid on ; title(Adding noise)end三种调制方式的性能比较load PeRate ;load PeRatep ;%补偿误差fpeask(15)=1e-3;fpefsk(9)=1e-3;fpepsk(24)=0.002;fpepsk(26)=1e-3;figure(1)semilogy(-6:length(fpeask)-7,fpeask,-6:length(fpefsk)-7,fpefsk,-30:length(fpepsk)-31,fpepsk),grid on ;title( legend( xlabel( ylabel(An

31、alysis Of Bit Error Rate);ASK , FSK , PSK );r/dB );Pe );figure(2)semilogy(-6:length(fpefsk)-7,fpeask);gridon;title(Bit Error Rate Of ASK);xlabel(r/dB );ylabel(PeASK );figure(3)semilogy(-6:length(fpefsk)-7,fpefsk);gridon;title(Bit Error Rate Of FSK);xlabel(r/dB );ylabel(PeFSK );figure(4)semilogy(-16:

32、length(fpepsk)-17,fpepsk);gridontitle(Bit Error Rate Of PSK);axis(-16,10,1e-3,1);xlabel(r/dB );ylabel(PePSK );三程序与调制解调波形3.1 2ASK 波形1 随机信号产生binary of receiving terminal01002003004005006007003信号噪声附加5解调出的基带信号3.2 . FSK1随机信号产生2FSK信号调制3信号噪声附加4接受信号解调Wave ofeceiving terminal(iriclliiiding noise)5 iiiiiiII5iiiiiii0100200300400500600700800After Passing BPF01002003004005006007