FM调制、解调 Matlab代码

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问题说明

待完成。。。。。太晚了都凌晨了，明天整。

这里写图片描述

%-------------------------------------%2FSK调制s=[1 0 1 1 0 0 1 0]; %原始数据f1= 200 ;%261.6256*2*pi;f2= 400 ;%391.9954*2*pi;Fs =  11025;t=0:1/(Fs-1)*10:1;m1=[];c1=[];B1=[];for n=1:length(s)    if s(n)==0;        m=ones(1,length(t));        c=sin(2*pi*f1*t);        b=zeros(1,length(t));    else s(n)==1;        m=ones(1,length(t));        c=sin(2*pi*f2*t);        b=ones(1,length(t));    end    m1=[m1 m];     c1=[c1 c];    B1=[B1 b];endfsk=c1.*m1;gcf = figure(1);subplot(311);plot(B1,'r')axis([1,length(B1),-0.2,1.2]);title('原始信号');%axis([0 100*length(s) -0.1 1.1]);grid on;subplot(312);plot(fsk(1:1000))title('2FSK信号');grid on; %sound(fsk,Fs,8);%wavwrite(fsk,Fs,8,'a.wav');%------------------------%高斯噪声no=0.1*randn(1,length(fsk));        %噪声fsk= 0.4*(fsk+no);%噪声加衰减subplot(313);plot(fsk(1:1000));title('噪声加衰减信号');saveas(gcf,'fm_01.png');%---------------------------------------------------------------------------%解调  % 使用带通滤波进行过滤b1=fir1(101,[0.1 0.6]);b2=fir1(101,[0.6 0.8]);  %设置带通参数H1=filter(b1,1,fsk);H2=filter(b2,1,fsk);          %经过带通滤波器后的信号gcf = figure(2);subplot(211);plot(H1);title('带通0.1-0.6 结果');subplot(212);title('带通0.6-0.8 结果');plot(H2);saveas(gcf,'fm_02.png');% 求绝对值（就是所谓的整流。。。）H1 = abs(H1);H2 = abs(H2);gcf = figure(3);subplot(211);title('低频整流');plot(H1);subplot(212);title('高频整流');plot(H2);%低通滤波器b3=fir1(101,0.1);H1_low=filter(b3,1,H1);H2_low=filter(b3,1,H2);saveas(gcf,'fm_03.png');gcf = figure(4);subplot(211);plot(H1_low);title('低频整流H1经过低频滤波');subplot(212);plot(H2_low);title('高频整流H1经过低频滤波');saveas(gcf,'fm_04.png');% 表决器z = ones(size(H1));z(H1_low>H2_low) = 0;%b4=fir1(101,0.1);b3=fir1(101,0.05);z=filter(b3,1,z);z(z>=0.5) = 1;z(z<0.5) = 0;gcf = figure(5);subplot(211);plot(B1);axis([1,length(z),-0.2,1.2]);title('原始信号');subplot(212);plot(z);axis([1,length(z),-0.2,1.2]);title('解调后信号');saveas(gcf,'fm_05.png');

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