信息對抗大作業(yè)

1、 信息對抗大作業(yè) 選題：（2）（8） 學院：通信工程學院 專業(yè)：通信工程專業(yè) 班級：011211 學號：01121081 姓名：田 翔 日期：2015.6.20目 錄封面1目錄2實驗（2）3一、實驗原理3二、數(shù)字調(diào)制技術的仿真實現(xiàn)5三、程序與調(diào)制解調(diào)波形15四、性能比較24實驗（8）25一、實驗目的25二、實驗原理25三、實驗仿真與實現(xiàn)26參考文獻28實驗(2) 使用Matlab構成一個加性高斯白噪聲情況下的2PSK調(diào)制解調(diào)系統(tǒng)，仿真分析使用信道編碼糾錯和不使用信道編碼時，不同信道信噪比情況下的系統(tǒng)誤碼率。 一 .數(shù)字調(diào)制與解調(diào)原理1.1 2ASK（1）2ASK2ASK就是把頻率、相位作為常量

2、，而把振幅作為變量，信息比特是通過載波的幅度來傳遞的。由于調(diào)制信號只有0或1兩個電平，相乘的結果相當于將載頻或者關斷，或者接通，它的實際意義是當調(diào)制的數(shù)字信號"1時，傳輸載波；當調(diào)制的數(shù)字信號為"0"時，不傳輸載波。公式為：1.2 2FSK2FSK可以看做是2個不同頻率的2ASK的疊加，其調(diào)制與解調(diào)方法與2ASK差不多，主要頻率F1和F2，不同的組合產(chǎn)生所要求的2FSK調(diào)制信號。公式如下：1.3 2PSK2PSK以載波的相位變化為基準，載波的相位隨數(shù)字基帶序列信號的1或者0而改變，通常用已經(jīng)調(diào)制完的載波的0或者表示數(shù)據(jù)1或者0，每種相位與之一一對應。二數(shù)字調(diào)制技術

3、的仿真實現(xiàn)本課程設計需要借助MATLAB的M文件編程功能，對2ASK.2PSK.2FSK進行調(diào)制與解調(diào)的設計，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上實現(xiàn)。1.2ASK代碼主函數(shù)close allclear alln=16;fc=1000000; bitRate=1000000;N=50;%noise=ti;noise=10;signal=source(n,N); %生成二進制代碼transmittedSignal=askModu(signal,bitRate,fc,N);%調(diào)制后信號signal1=gussian(transmittedSignal,noise);

4、%加噪聲configueSignal=demoASK(signal1,bitRate,fc,n,N);source代碼function sendSignal=source(n,N) sendSignal=randint(1,n) bit=; for i=1:length(sendSignal) if sendSignal(i)=0 bit1=zeros(1,N); else bit1=ones(1,N); end bit=bit,bit1; end figure(1) plot(1:length(bit),bit),title('transmitting of binary')

5、,grid on; axis(0,N*length(sendSignal),-2,2);endaskModu代碼function transmittedSignal=askModu(signal,bitRate,fc,N)%signal為輸入信號，bitrate為bit速率，fc調(diào)制信號頻率，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)

6、transmittedSignal=transmittedSignal,signal(i)*c; endfigure(2) %畫調(diào)制圖plot(1:length(transmittedSignal),transmittedSignal);title('Modulation of ASK');grid on;figure(3)%畫頻譜實部m=0:length(transmittedSignal)-1;F=fft(transmittedSignal);plot(m,abs(real(F),title('ASK_frequency-domain analysis real&#

7、39;);grid on;%figure(4) 畫頻譜虛部%plot(m,imag(F);title('ASK_frequency-domain analysis imag');%grid on;endCheckRatePe代碼function PeWrong=CheckRatePe(signal1,signal2,s)rights=0;wrongs=0;for ki=1:s-2 if(signal1(ki)=signal2(ki) rights=rights+1; else wrongs=wrongs+1; endendPeWrong=wrongs/(wrongs+right

8、s);enddemoASK代碼function bitstream=demoASK(receivedSignal,bitRate,fc,n,N) load num signal1=receivedSignal; signal2=abs(signal1); %ÕûÁ÷ signal3=filter(num1,1,signal2); %LPF,°üÂç¼ì²¨ IN=fix(length(num1)/2); %ÑÓ³Ùʱ

9、;¼ä bitstream=; LL=fc/bitRate*N; i=IN+LL/2; while (i<=length(signal3) %Åоö bitstream=bitstream,signal3(i)>=0.5; i=i+LL; end figure(6) subplot(3,1,1); %接收波形 plot(1:length(signal1),signal1);title('Wave of receiving terminal(including noise)');grid on; subpl

10、ot(3,1,2);%接收整流后波形 plot(1:length(signal2),signal2);title('Wave of commutate');grid on; subplot(3,1,3);%包絡檢波波形 plot(1:length(signal3),signal3);title('Wave of LPF');grid on; bit=; for i=1:length(bitstream) if bitstream(i)=0 bit1=zeros(1,N); else bit1=ones(1,N); end bit=bit,bit1; end fi

11、gure(7)%解調(diào)后的二進制波形 plot(bit),title('binary of receiving terminal'),grid on; axis(0,N*length(bitstream),-2.5,2.5);endgussian代碼 %加高斯白噪聲function signal=gussian(transmittedSignal,noise) signal=sqrt(2)*transmittedSignal; signal=awgn(signal,noise); figure(5) plot(1:length(signal),signal); title(

12、9;Wave including noise'),grid on;end/ fsk主函數(shù)代碼close allclear alln=16;%二進制代碼長度f1=18000000;%頻率1f2=6000000;%頻率2bitRate=1000000;%bit速率N=50;%碼元寬度%noise=ti;noise=10;%家性噪聲大小signal=source(n,N);%產(chǎn)生二進制代碼transmittedSignal=fskModu(signal,bitRate,f1,f2,N);%調(diào)制signal1=gussian(transmittedSignal,noise);%加噪聲confi

13、gueSignal=demoFSK(signal1,bitRate,f1,f2,N);%解調(diào)source代碼%二進制信號產(chǎn)生函數(shù)function sendSignal=source(n,N) sendSignal=randint(1,n) bit=; for i=1:length(sendSignal) if sendSignal(i)=0 bit1=zeros(1,N); else bit1=ones(1,N); end bit=bit,bit1; end figure(1) plot(bit),title('transmitting of binary'),grid on;

14、 axis(0,N*length(sendSignal),-2.5,2.5);endfskModu代碼%頻率調(diào)制函數(shù)function transmittedSignal=fskModu(signal,bitRate,f1,f2,N) t=linspace(0,1/bitRate,N); c1=sin(2*pi*t*f1);%調(diào)制信號1 c2=sin(2*pi*t*f2);%調(diào)制信號2 transmittedSignal=; for i=1:length(signal)%調(diào)制 if signal(i)=1 transmittedSignal=transmittedSignal,c1; else

15、transmittedSignal=transmittedSignal,c2; end endfigure(2) %畫調(diào)制后波形圖 plot(1:length(transmittedSignal),transmittedSignal);title('Modulation of FSK');grid on;figure(3) %畫調(diào)制后頻譜圖m=0:length(transmittedSignal)-1;F=fft(transmittedSignal);plot(m,abs(real(F),title('ASK_frequency-domain analysis real

16、');grid on;enddemoFSK代碼function bitstream=demoFSK(receivedSignal,bitRate,f1,f2,N) load num signal1=receivedSignal; signal2=filter(gaotong,1,signal1); %通過HPF，得到高通分量 signal3=abs(signal2); %整流 signal3=filter(lowpass,1,signal3); %通過低通，形成包絡 bitstream=; IN1=fix(length(lowpass)/2)+fix(length(gaotong)/2

17、); %延遲時間 bitstream1=; LL=N; %每個bit的抽樣點數(shù) i=IN1 +LL/2; while (i<=length(signal3) %判決 bitstream1=bitstream1,signal3(i)>=0.5; i=i+LL; end bitstream1 figure(5) subplot(3,1,1); plot(1:length(signal1),signal1);title('Wave of receiving terminal(including noise)');grid on; subplot(3,1,2); plot(

18、1:length(signal2),signal2);title('After Passing HPF');grid on; subplot(3,1,3); plot(1:length(signal3),signal3);title('After Passing LPF');grid on; signal4=filter(daitong,1,signal1); %通過BPF得到低頻分量 signal5=abs(signal4); %整流 signal5=filter(lowpass,1,signal5); %通過LPF，形成包絡 IN2=fix(length(l

19、owpass)/2)+fix(length(daitong)/2); %延遲時間 bitstream2=; LL=N; %每個bit的的抽樣點數(shù) i=IN2 +LL/2; while (i<=length(signal5) %判決 bitstream2=bitstream2,signal5(i)>=0.5; i=i+LL; end bitstream2 figure(6) subplot(3,1,1); plot(1:length(signal1),signal1);title('Wave of receiving terminal(including noise)'

20、;);grid on; subplot(3,1,2); plot(1:length(signal4),signal4);title('After Passing BPF');grid on; subplot(3,1,3); plot(1:length(signal5),signal5);title('After Passing LPF');grid on; for i=1:min(length(bitstream1),length(bitstream2) %判決 if(bitstream1(i)>bitstream2(i) bitstream(i)=1;

21、else bitstream(i)=0; end end bitstream bit=; %接收端波形 for i=1:length(bitstream) if bitstream(i)=0 bit1=zeros(1,N); else bit1=ones(1,N); end bit=bit,bit1; end figure(7) plot(bit),title('binary of receiving terminal'),grid on; axis(0,N*length(bitstream),-2.5,2.5); end CheckRatePe代碼function PeWro

22、ng=CheckRatePe(signal1,signal2,s)rights=0;wrongs=0;for ki=1:s-2 if(signal1(ki)=signal2(ki) rights=rights+1; else wrongs=wrongs+1; endendPeWrong=wrongs/(wrongs+rights);endgussian代碼function signal=gussian(transmittedSignal,noise) signal=sqrt(2)*transmittedSignal; signal=awgn(signal,noise); figure(4) p

23、lot(1:length(signal),signal),title('Adding Noise'); grid on;end2psk主函數(shù)代碼close allclear alln=16;%二進制碼長fc=1000000;%載波頻率bitRate=1000000;信息頻率N=50;%碼寬noise=10;%信道加性噪聲大小signal=source(n,N);生成二進制代碼transmittedSignal=bpskModu(signal,bitRate,fc,N);對信號進行調(diào)制并進行頻譜分析signal1=gussian(transmittedSignal,noise)%

24、加信道噪聲configueSignal=demoBPSK(signal1,bitRate,fc,n,N);%信號解調(diào)source代碼function sendSignal=source(n,N) sendSignal=randint(1,n) bit=; for i=1:length(sendSignal) if sendSignal(i)=0 bit1=zeros(1,N); else bit1=ones(1,N); end bit=bit,bit1; end figure(1) plot(bit),title('transmitting of binary'),grid o

25、n; axis(0,N*length(sendSignal),-2.5,2.5);endbpskModu代碼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; else transmittedSigna

26、l=transmittedSignal,c2; end endfigure(2) % 畫調(diào)制圖plot(1:length(transmittedSignal),transmittedSignal);title('Modulation of BPSK');grid on;figure(3)%畫頻譜圖m=0:length(transmittedSignal)-1;F=fft(transmittedSignal);plot(m,abs(real(F),title('BPSK_frequency-domain analysis real');grid on;endChe

27、ckRatePe代碼function PeWrong=CheckRatePe(signal1,signal2,s)rights=0;wrongs=0;for ki=1:s-2 if(signal1(ki)=signal2(ki) rights=rights+1; else wrongs=wrongs+1; endendPeWrong=wrongs/(wrongs+rights);enddemoBPSK代碼function bitstream=demoBPSK(receivedSignal,bitRate,fc,n,N) load num %讀取num存儲的低通濾波用的數(shù)據(jù) signal1=re

28、ceivedSignal; t=linspace(0,1/bitRate,N); c=sin(2*pi*t*fc); signal=; for i=1:n signal=signal,c; end signal2=signal1.*signal; %乘同頻同相sin signal3=filter(num1,1,signal2); %LPF,包絡檢波3 IN=fix(length(num1)/2); %Ñ延遲時間 bitstream=; LL=fc/bitRate*N; i=IN+LL/2; while (i<=length(signal3) %判決 bitstream=bits

29、tream,signal3(i)>=0; i=i+LL; end figure(5) subplot(3,1,1);%畫接收的包含噪聲的波形 plot(1:length(signal1),signal1);title('Wave of receiving terminal(including noise)');grid on; subplot(3,1,2);%相干解調(diào)波形 plot(1:length(signal2),signal2);title('After Multipling sin Fuction');grid on; subplot(3,1,3)

30、;%包絡檢波波形 plot(1:length(signal3),signal3);title('Wave of LPF');grid on; bit=; for i=1:length(bitstream) if bitstream(i)=0 bit1=zeros(1,N); else bit1=ones(1,N); end bit=bit,bit1; end figure(6)二進制接收信號波形 plot(bit);title('binary of receiving terminal');grid on; axis(0,N*length(bitstream),

31、-2.5,2.5);endgussian代碼function signal=gussian(transmittedSignal,noise) signal=sqrt(2)*transmittedSignal; signal=awgn(signal,noise); figure(4) plot(1:length(signal),signal),grid on; title('Adding noise')end三種調(diào)制方式的性能比較:load PeRate;load PeRatep;%補償誤差fpeask(15)=1e-3;fpefsk(9)=1e-3;fpepsk(24)=0.0

32、02;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('Analysis Of Bit Error Rate');legend('ASK','FSK','PSK');xlabel('r/dB');ylabel('Pe');figure(2)semilogy(-6:length(fpefs

33、k)-7,fpeask);grid on;title('Bit Error Rate Of ASK');xlabel('r/dB');ylabel('PeASK');figure(3)semilogy(-6:length(fpefsk)-7,fpefsk);grid on;title('Bit Error Rate Of FSK');xlabel('r/dB');ylabel('PeFSK');figure(4)semilogy(-16:length(fpepsk)-17,fpepsk);grid on;title('Bit Error Rate Of PSK');axis(-16,10,1e-3,1);xlabel('r/dB');ylabel('PePSK');三程序與調(diào)制解調(diào)波形3.1 2ASK波形1隨機信號產(chǎn)生2ASK信號調(diào)制3信號噪聲附加4接受信號解調(diào)5解調(diào)出的基帶信號3.2FSK1隨機信號產(chǎn)生2FSK信號調(diào)制3信號噪聲附加4接受信號解調(diào)5解調(diào)出的基帶信號3.3PSK1隨機信號產(chǎn)生2FSK信號調(diào)制3信號噪聲附加4接受信號解調(diào)5解調(diào)出的基帶信號3.4誤碼率分析1.2ASK誤碼率分析2