what are the hamming, fft, ifft functions?
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% Signal parameters:
f = [ 440 880 1000 2000 ]; % frequencies
M = 256; % signal length
Fs = 5000; % sampling rate
% Generate a signal by adding up sinusoids:
x = zeros(1,M); % pre-allocate 'accumulator'
n = 0:(M-1); % discrete-time grid
for fk = f;
x = x + sin(2*pi*n*fk/Fs);
end
% Filter parameters:
L = 257; % filter length
fc = 600; % cutoff frequency
% Design the filter using the window method:
hsupp = (-(L-1)/2:(L-1)/2);
hideal = (2*fc/Fs)*sinc(2*fc*hsupp/Fs);
h = hamming(L)' .* hideal; % h is our filter
% Choose the next power of 2 greater than L+M-1
Nfft = 2^nextpow2(L+M-1);
% Zero pad the signal and impulse response:
xzp = [ x zeros(1,Nfft-M) ];
hzp = [ h zeros(1,Nfft-L) ];
X = fft(xzp); % signal
H = fft(hzp); % filter
Y = X .* H;
y = ifft(Y);
relrmserr=norm(imag(y))/norm(y) % check... should be zero
y = real(y);
subplot(2,1,1), plot(x)
subplot(2,1,2), plot(y)
grid on
my low pass filter works but I don't want to use hamming, fft and ifft. Instead of these I want to use hamming, fft, ifft functions. I found some codes about them but it didn't work. Could you help me please?
3 commentaires
Image Analyst
le 4 Jan 2013
I don't understand - you say you don't want to use those three functions and then you say you want to use them instead of themselves. What does all that mean? Do you want to use them or not?
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