基于MATLAB的數(shù)字調(diào)制

基于MATLAB的數(shù)字調(diào)制2ASK、2FSK、2PSK數(shù)字調(diào)制系統(tǒng)的Matlab實(shí)現(xiàn)及性能分析與比較(1)2ASK引言：數(shù)字帶通傳輸系統(tǒng)為了進(jìn)行長(zhǎng)距離傳輸，克服傳輸失真，傳輸損耗，同時(shí)保證帶內(nèi)特性。必須對(duì)數(shù)字信號(hào)進(jìn)行載波調(diào)制，將信號(hào)頻譜搬移到高頻段才能在信道中傳輸，因而現(xiàn)代通信系統(tǒng)采取數(shù)字調(diào)制技術(shù)。通過(guò)數(shù)字基帶信號(hào)對(duì)載波某些參量進(jìn)行控制，使之隨機(jī)帶信號(hào)的變化而變化。根據(jù)控制載波參量大的不同，數(shù)字調(diào)制有調(diào)幅(ASK)，調(diào)頻(FSK)，調(diào)相(PSK)三種基本形式。Matlab用于仿真，分析和修改，還可以應(yīng)用圖形界面功能GUI能為仿真系統(tǒng)生成一個(gè)人機(jī)交互界面，便于仿真系統(tǒng)的操作，因此采用matlab對(duì)數(shù)字系統(tǒng)進(jìn)行仿真。通過(guò)對(duì)系統(tǒng)的仿真，我們可以更加直觀的了解數(shù)字調(diào)制系統(tǒng)的性能()及影響性能的因關(guān)鍵詞：數(shù)字.系統(tǒng).性能.ASK.FSK.PSK.Matlab.仿真.一.數(shù)字調(diào)制與解調(diào)原理2ASK2ASK就是把頻率、相位作為常量，而把振幅作為變量，信息比特是通過(guò)(Acosot,當(dāng)a=1相當(dāng)于將載s頻或(〈斷，或者c接通，k它的實(shí)際意義是當(dāng)調(diào)制的數(shù)字信號(hào)k2ASK0，當(dāng)a=0k"1時(shí)，傳輸載波；當(dāng)調(diào)制的數(shù)字信號(hào)為"0"時(shí)，不傳輸載波。2FSK2k2k2PSK2PSK以載波的相位變化為基準(zhǔn)，載波的相位隨數(shù)字基帶序列信號(hào)的1或種相位與之一一對(duì)應(yīng)。二．?dāng)?shù)字調(diào)制技術(shù)的仿真實(shí)現(xiàn)調(diào)的設(shè)計(jì)，并繪制出調(diào)制與解調(diào)后的波形，誤碼率的情況分析，軟件仿真可在已有平臺(tái)上實(shí)現(xiàn)。代碼主函數(shù)closeallclearalln=16;fc=1000000;bitRate=1000000;N=50;%noise=ti;noise=10;signal=source(n,N);%生成二進(jìn)制代碼transmittedSignal=askModu(signal,bitRate,fc,N);%調(diào)制后信號(hào)signal1=gussian(transmittedSignal,noise);%加噪聲configueSignal=demoASK(signal1,bitRate,fc,n,N);functionsendSignal=source(n,N)sendSignal=randint(1,n)bit=[];fori=1:length(sendSignal)ifsendSignal(i)==0bit1=zeros(1,N);bit1=ones(1,N);bit=[bit,bit1];figure(1)plot(1:length(bit),bit),title('transmittingofaxis([0,N*length(sendSignal),-2,2]);functiontransmittedSignal=askModu(signal,bitRate,fc,N)%signal%signal=[00101101];%bitRate=1000000;%fc=1000000;%N=32;t=linspace(0,1/bitRate,N);c=sin(2*pi*t*fc);transmittedSignal=[];fori=1:length(signal)transmittedSignal=[transmittedSignal,signal(i)*c];figure(2)%畫調(diào)制圖plot(1:length(transmittedSignal),transmittedSignal);title('Modufigure(3)%畫頻譜實(shí)部m=0:length(transmittedSignal)-1;F=fft(transmittedSignal);plot(m,abs(real(F))),title('ASK_frequency-domainanalysisreal');%figure(4)畫頻譜虛部%plot(m,imag(F));title('ASK_frequency-domainanalysisimag');%gridon;functionPeWrong=CheckRatePe(signal1,signal2,s)rights=0;wrongs=0;forki=1:s-2if(signal1(ki)==signal2(ki))rights=rights+1;wrongs=wrongs+1;PeWrong=wrongs/(wrongs+rights);functionbitstream=demoASK(receivedSignal,bitRate,fc,n,N)loadnumsignal1=receivedSignal;signal2=abs(signal1);signal3=filter(num1,1,signal2);%??á÷%LPF,°ü???ì2¨IN=fix(length(num1)/2);bitstream=[];LL=fc/bitRate*N;i=IN+LL/2;while(i<=length(signal3))%?ó3ùê±??%?D??bitstream=[bitstream,signal3(i)>=];figure(6)subplot(3,1,1);%接收波形plot(1:length(signal1),signal1);title('Waveofreceivingterminal(includingnoise)');gridon;subplot(3,1,2);%接收整流后波形plot(1:length(signal2),signal2);title('Waveofsubplot(3,1,3);%包絡(luò)檢波波形plot(1:length(signal3),signal3);title('WaveofLPF');gridbit=[];fori=1:length(bitstream)ifbitstream(i)==0bit1=zeros(1,N);bit1=ones(1,N);bit=[bit,bit1];figure(7)%解調(diào)后的二進(jìn)制波形plot(bit),title('binaryofreceivingterminal'),gridon;axis([0,N*length(bitstream),,]);gussian代碼%加高斯白噪聲functionsignal=gussian(transmittedSignal,noise)signal=sqrt(2)*transmittedSignal;signal=awgn(signal,noise);figure(5)plot(1:length(signal),signal);title('Waveincludingnoise'),gridon;signal;%乘同頻同相sinbit=[];signal3=filter(num1,1,signal2);IN=fix(length(num1)/2);bitstream=[];LL=fc/bitRate*N;i=IN+LL/2;while(i<=length(signal3))%LPF,包絡(luò)檢波3%?延遲時(shí)間%判決bitstream=[bitstream,signal3(i)>=0];figure(5)subplot(3,1,1);%畫接收的包含噪聲的波形plot(1:length(signal1),signal1);title('Waveofreceivingterminal(includingnoise)');gridon;subplot(3,1,2);%相干解調(diào)波形plot(1:length(signal2),signal2);title('AfterMultiplingsinsubplot(3,1,3);%包絡(luò)檢波波形plot(1:length(signal3),signal3);title('WaveofLPF');grid三種調(diào)制方式的性能比較:fori=1:length(bitstream)ifbitstream(i)==0bit1=zeros(1,N);bit1=ones(1,N);bit=[bit,bit1];figure(6)二進(jìn)制接收信號(hào)波形plot(bit);title('binaryofreceivingterminal');gridon;axis([0,N*length(bitstream),,]);gussian代碼functionsignal=gussian(transmittedSignal,noise)signal=sqrt(2)*transmittedSignal;signal=awgn(signal,noise);figure(4)plot(1:length(signal),signal),gridon;title('Addingnoise')%補(bǔ)償誤差fpeask(15)=1e-3;fpefsk(9)=1e-3;fpepsk(24)=;fpepsk(26)=1e-3;figure(1)semilogy(-6:length(fpeask)-7,fpeask,-6:length(fpefsk)-7,fpefsk,-30:length(fpepsk)-31,fpepsk),gridon;title('AnalysisOfBitErrorRate');legend('ASK','FSK','PSK');xlabel('r/dB');ylabel('Pe');figure(2)semilogy(-6:length(fpefsk)-7,fpeask);gridon;title('BitErrorRateOfASK');xlabel('r/dB');ylabel('PeASK');figure(3)semilogy(-6:length(fpefsk)-7,fpefsk);gridon;title('BitErrorRateOfFSK');xlabel('r/dB');ylabel('PeFSK');figure(4)semilogy(-16:length(fpepsk)-17,fpepsk);gridon;title('BitErrorRateOfPSK');axis([-16,10,1e-3,1]);xlabel('r/dB');ylabel('PePSK');三．程序與調(diào)制解調(diào)波形1．隨機(jī)信號(hào)產(chǎn)生誤碼率分析誤碼率分析誤碼率分析誤碼率分析經(jīng)過(guò)緊張而有辛苦的一周的通信原理課程設(shè)計(jì)，當(dāng)辛苦的汗水換來(lái)的是成功的喜悅時(shí)，感覺自己又完成了對(duì)自己的一個(gè)新的超越，這大大增加了我的自信心，也是對(duì)自己的能力的肯定。但更重要的時(shí)課程設(shè)計(jì)是理論與實(shí)踐的結(jié)合，在此過(guò)程中可謂收獲頗豐，這一點(diǎn)遠(yuǎn)比結(jié)果重要，不僅提高了分析問(wèn)題和解決問(wèn)題的能力，5.參考文獻(xiàn)[1]樊昌信.通信原理(第6版).國(guó)防工業(yè)出版社，2006，09[2]黎洪松.數(shù)字通信原理.西安電子系科技大學(xué)出版社，2005，07[3]任嘉偉.數(shù)字頻帶通信系統(tǒng)計(jì)算機(jī)仿真[J].電腦知識(shí)與技術(shù)，2008，07[4]呂躍廣通信系統(tǒng)仿真.電子工業(yè)出版社,[5]席在芳等基于SIMULINK的現(xiàn)代通信