发布时间 : 星期六 文章2PSK数字信号的调制与解调更新完毕开始阅读
%Comparator
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 判定并输出波形
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% High=2.5; Low=-2.5;
vt=0;%设立比较标准 error=0;
len1=length(so); for ii=1:len1 if so(ii) >= vt Vs(ii)=High; else
Vs(ii)=Low; end end Vo=Vs;
subplot(325);
plot (t,Vo), title('解调后输出信号'), axis([0 2e-4 -5 5]) grid on;
xlabel('时间 (s)'), ylabel('幅度(V)')
set (gcf, 'num', 'off', 'name', ['系统信号解调波形'... blanks(10)]);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 系统调制信号频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% T=t(end); df=1/T;
N=length(ask); f=(-N/2:N/2-1)*df; figure(3)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 信源频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% xf=fftshift(abs(fft(x))); subplot(221) plot(f,xf)
title('信源频谱')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 调制信号频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% askf=fftshift(abs(fft(ask))); subplot(222)
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plot(f,askf)
title('调制信号频谱')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 噪音信号频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% noisef=fftshift(abs(fft(noise))); subplot(223) plot(f,noisef)
title('噪音信号频谱')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 调制后加噪音信号频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% asknf=fftshift(abs(fft(askn))); subplot(224) plot(f,asknf)
title('调制后加噪音信号频谱')
set (gcf, 'num', 'off', 'name', ['系统调制信号频谱'... blanks(10)]);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 通过带通滤波后信号频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% figure(4)
fasknf=fftshift(abs(fft(faskn))); subplot(221) plot(f,fasknf)
title(' 通过带通滤波后信号频谱')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 通过相乘器后信号频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% cmf=fftshift(abs(fft(cm))); subplot(222) plot(f,cmf)
title(' 通过相乘器后信号频谱') sof=fftshift(abs(fft(so))); subplot(223) plot(f,sof)
title('通过低通滤波器后输出信号频谱')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 通过判决解调后输出信号频谱
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Vof=fftshift(abs(fft(Vo))); subplot(224) plot(f,Vof)
title('通过判决解调后输出信号频谱')
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set (gcf, 'num', 'off', 'name', ['系统解调信号频谱'... blanks(10)]);
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