qamdet.m

交全面的给出了好几种调制解调方案的matlab代码,又ASK,BPSK,FSK,QAM等的源代码 对通信领域的研究人员很有帮助

function [xn,x]=qamdet(y,fs,fb,fc);
%
% Usage:[xn,x]=qamdet(y,fs,fb,fc);BBI
% 2000;y为调制信号;xn为解调输出的二进制码流向量,x为解调输出的脉冲信号波形
if nargin<4;fc=2;end;
if nargin<3;fb=1;end;
if nargin<2;fs=32;end;
if nargin<1;y=qam([1 1 0 0 1 1 1 1 0 0 0 0 0 0 1 1]);end;
dt=1/fs;t=0:dt:(length(y)-1)*dt;
I=y.*cos(2*pi*fc*t);Q=-y.*sin(2*pi*fc*t);
[b,a]=butter(2,2*fb/fs);tstr=('16QAM');
I=filtfilt(b,a,I);Q=filtfilt(b,a,Q);
% ? plot(i,I,i,Q);
m=4*fs/fb;N=length(y)/m;n=(.6:1:N)*m;n=fix(n);
In=I(n);Qn=Q(n);xn=four2two([In Qn]);
nn=length(xn);xn=[xn(1:nn/2);xn(nn/2+1:nn)];
xn=xn(:);xn=xn';x=[I;Q];
%--------------------------------------------------
if nargout<1;
    c='bbbbbbbbrrrrrrrr';
    subplot(211);plot(t,y);title('Input');
    subplot(212);plot(t,x);set(gca,'ygrid','on');v=axis;
    for i=1:4*N;
        ci=rem(i,16);ci=ci+(ci==0)*16;ci=c(ci);
        text((2*i-1)*m*dt/8,v(4)*.8,int2str(xn(i)),'color',ci);
    end;title('Output');
    set(gcf,'num','off','name',...
        ['Coherent Detection of,''tstr blanks(10)','BBI 2000']);
    zoom xon;
end;