function Y=pulsetrain2(x,y,Tx,Ty)
minx=min(x);
maxx=max(x);
Nminx=sign(minx)*ceil(abs(minx/Tx));
Nmaxx=sign(maxx)*ceil(abs(maxx/Tx));
miny=min(y);
maxy=max(y);
Nminy=sign(miny)*ceil(abs(miny/Ty));
Nmaxy=sign(maxy)*ceil(abs(maxy/Ty));
sx=size(x);
sy=size(y);
sumx=zeros(sx);
sumy=zeros(sy);
T2=0.0001;
for tx=Nminx:1:Nmaxx,
   xdel=Tx*tx;
   rectx=0.5*(sign((x+T2)-xdel)-sign((x-T2)-xdel));
   sumx=sumx+rectx;
end
for ty=Nminy:1:Nmaxy,
   ydel=Ty*ty;
   recty=0.5*(sign((y+T2)-ydel)-sign((y-T2)-ydel));
   sumy=sumy+recty;
end
Y=sumy'*sumx;