实验三单双极性归零码波形和频谱八、程序代码% initializeclear;fs=512*1000;T=1;N=T*fs;dt=1/fs;t=-T/2:dt:(T/2-dt);df=1/T;f=-fs/2:df:(fs/2-df);L=100;M=N/L;Tb=L*dt;Rb=1/Tb;SINGLE=zeros(1,N);DOUBLE=zeros(1,N);% youdecidethelengthofeachsignemp_rate=input('输入占空比：');looptime=100;forkk=1:looptime% originalbinaryflowimp=round(rand(1,M));% generatetheactualwaveinsignalpoleformsingle=zeros(1,N);forii=1:emp_rate*Lforjj=1:Msingle(ii+(jj-1)*L)=imp(jj);endend% andindoublepoleformdouble=single;forii=1:Nifsingle(ii)==0double(ii)=-1;endendSINGLE=SINGLE+t2f(single,fs)/looptime;DOUBLE=SINGLE+t2f(double,fs)/looptime;end% let'splotthemoutfigure(1)subplot(2,1,1)plot(t,single);axis([-T/2,T/2,-0.2,1.2])title('单极性 NRZ波形')xlabel('时间(s)')ylabel('幅度(V)')subplot(2,1,2)semilogy(f,abs(SINGLE).^2);axis([-10*Rb,10*Rb,1e-10,20])title('单极性 NRZ功率谱')xlabel('频率(Hz)')ylabel('幅度(W/Hz)')figure(2)subplot(2,1,1)plot(t,double);axis([-T/2,T/2,-1.2,1.2])title('双极性 NRZ波形')xlabel('时间(s)')ylabel('幅度(V)')subplot(2,1,2)semilogy(f,abs(DOUBLE).^2);axis([-10*Rb,10*Rb,1e-10,20])title('双极性 NRZ功率谱')xlabel('频率(Hz)')ylabel('幅度(W/Hz)')
