pulse.m

16QAM的MATLAB调制解调仿真

function [y,m] =pulse (x, m, Kmod);
%
% Usage:y=pulse (x, m, Kmod);   BBI 2000
if nargin<3; Kmod=1;             end;
if nargin<2; m=16;              end;
if nargin<1; x=randint(1, 32);   end;
di=.5;  Kmod=rem (Kmod, 5); Kmod= (Kmod==0)*5+Kmod;
if Kmod==1;
   xx= [x; x]; xx=xx (:)' ;tstr='unipolor NRZ';
elseif Kmod==2;
   xx= [x; x]; xx=2*xx (:)' -1 ;tstr='polor NRZ';
elseif Kmod==3;
  xx= [x;zeros(size (x))]; xx=xx (:)';di=.2;  tstr='uipolor RZ';
elseif Kmod==4;
  I=find (x==1); x1=x (I);x1=rem (cumsun (x1),2) *2-1;xx=x;
  xx (I)=x1;
  xx= [xx;zeros (size (x))];xx=xx (:),;di=.2; tstr=' Bipolor RZ';
  
end;
y=xx;
for i=1: fix (m/2) -1;  y= [y; xx];   end;y=y (:)';
%----------------------------
if nargout<1;
    subplot (211); plot (1+ (1: length (y))/m,y);hold on;
    v=axis;axis ( [v (1: 2) -1.2 1.5]);zoom xon;
    if Kmod==2|Kmod==0;
       plot ( [0 v (2)],[0 0],':');
   end;hold off;
   set(gcf, 'num', ' off',' name',['Binary Pulse Generator, ' tstr ',' blanks (10) ' BBI 2000']);
   for i=1: length (x);
       text (i+di, 1.3, int2str (x (i)),'color','b');
   end;
   title (' Pulse Signal');
   n=length (y);y=fft (y) /n;y=abs (y (1: fix (n/2)))*2;
   I=find (y<1e-04);y(I) =1e-04;y=20*log10(y);
   f1=m/n;f=0: f1: (length (y) -1) *f1;
   subplot (212) ; plot(f, x, f, y); h=get (gca,' children');
   title(' Power Spectrum');xlabel (' f/fb');zoom xon;
end;