constel.m

个人硕士论文的关于数字接收机调制解调方面的matlab程序

function c=constel(x,fs,fb,fc);
%Usage:ph=phdet(x,fs,fc); BBI 2000
if nargin<4;fc=2; end ;
if nargin<3;fb=1; end ;
if nargin<2;fs=32; end;
if nargin<1;
   t= (0:255)/fs; x=cos(2*pi*fc*t+.25*pi);
end;
N=length(x); m=2*fs/fb; n=fs/fc;
i1=m-n; i=1; pho=(i1-1)*2*pi/n;
while i<=N/m;
    xi=x(i1:i1+n-1); y=2*fft(xi)/n; c(i)=y(2);
    i=i+1; i1=i1+m;
end;
%-----------------------------------------------
if nargout<1;
    cmax=max(abs(c));
    ph=(0:5:360)*pi/180; plot(1.414*cos(ph),1.414*sin(ph),'c');
    hold on;
    for i=1:length(c);
        ph=angle(c(i))-pho+pi; %+pi/2;
        a=abs(c(i))/cmax*1.414;
        plot(a*cos(ph),a*sin(ph),'r*');
    end;
    plot([-1.5 1.5],[0 0],'k:',[0 0],[-1.5 1.5],'k:');
    hold off; axis equal; axis([-1.5 1.5 -1.5 1.5]);
end