%create kernel matrix
slen=100;
M=dft(slen);

%example one impulse response delayed by one
if 1==1
  figure;
  x=zeros(1,slen);
  x(2)=1;
  subplot(311)
  stem(x); xlabel('signal')
  subplot(312)
  stem(real(x*M)); xlabel('real part');
  subplot(313) 
  stem(imag(x*M)); xlabel('imag part');
  title('delayed impulse response')
end
