bpskdet.m

对ASK调制解调进行了仿真,包括程序仿真和模型仿真

function [xn,x]=bpskdet(y,Kmod,fs,fb,fc,rd);
if nargin<6; rd=0; end;
if nargin<5; fc=2; end;
if nargin<4; fb=1; end;
if nargin<3; fs=32; end;
if nargin<2; Kmod=1; end;
if nargin<1; y=bpsk([0 0 1 1 1 0 0 1 0 1]); end;
dt=1/fs; t=0: dt:(length(y) -1)*dt;
x=y.*sin(2*pi*fc*t);
[b,a]=butter(2, 2*fb/fs);
x=-filtfilt(b,a,x);
m=fs/fb; N=length(y)/m; n=(.75:1:N)*m;
xn=(sign(x(n))+1)/2;
if Kmod ==1;
    tstr='BPSK';
elseif Kmod ==2;
    xn=xor(xn,[rd xn(1:N-1)]); tstr='DPSK';
end;
if nargout<1;
    c='bbbbbbbbrrrrrrrr'; 
    subplot(211);plot(t,y);   title('Input');
    subplot(212);plot (t,x,t,sign(x)*.5);
    set (gca,'ygrid','on'); v=axis;
    for i=1:N;
        ci=rem(i,16); ci=ci+ (ci==0)*16;ci=c(ci);
        text ((2*i-1)*m*dt/2,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;