www.pudn.com > voiceprocessingtoolbox.rar > fftZeroPadding01.m

% This example demos the effect of zero-padding of DFT 
 
for i=1:3 
	L = 5; N = 20*i; 
	x = [ones(1,L), zeros(1,N-L)]; 
	subplot(3,3,i*3-2); 
	stem(x); 
	title(sprintf('x[n] with N=%d',N)); 
	set(gca, 'xlim', [-inf inf]); 
 
	omega=((1:N)-ceil((N+1)/2))*(2*pi/N); 
	X = fft(x); 
	magX = fftshift(abs(X)); 
	subplot(3,3,i*3-1); 
	plot(omega, magX, '.-'); 
	title('Magnitude of DFT of x[n]') 
	set(gca, 'xlim', [-inf inf]); 
 
	phase=fftshift(angle(X)); 
	subplot(3,3,i*3); 
	plot(omega, phase, '.-'); 
	title('Phase of DFT of x[n]') 
	set(gca, 'xlim', [-inf inf]); 
	set(gca, 'ylim', [-pi pi]); 
end