clf();
X=[0 0.5 1 0.5];
XF=[X 0];
WF=[X X X 0];
f=-0.5:0.25:0.5;
f1=-0.75:0.125:0.75;
HF=[0 1 1 1 0];
f2=[-0.126,-0.125:0.125:0.125,0.126];
for i=1:5
    YF(i)=WF(i)*HF(i);
end
f3=[-0.126 -0.125 0 0.125 0.126];
a=gca();
a.y_location="origin";
subplot(211);
plot2d(f,XF);
xtitle('spectrum of XF');
a.y_location="origin";
subplot(212);
plot2d(f1,WF);
xtitle('spectrum of WF');
xset('window',1);
b=gca();
b.y_location="origin";
subplot(211);
plot2d(f2,HF);
xtitle('spectrum of HF');
b.y_location="origin";
subplot(212);
plot2d(f3,YF);
xtitle('spectrum of YF');