hanning ,hamming window in matlab?
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how do Hanning and Hamming window in matlab?
when must I do these window after DFT signal or before DFT signal?
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Accepted Answer
Wayne King
on 26 Nov 2013
Edited: Wayne King
on 26 Nov 2013
Before you take the DFT
hamming() or hann()
t = 0:0.001:1-0.00;
x = cos(2*pi*100*t)+randn(size(t));
winvec = hamming(length(x)); % hann(length(x));
xdft = fft(x'.*winvec);
plot(abs(xdft))
6 Comments
Wayne King
on 26 Nov 2013
You can put them in a matrix and multiply them all at once.
X = randn(100,20);
h = hamming(100);
h = repmat(h,1,20);
X = X.*h;
More Answers (2)
Wayne King
on 27 Nov 2013
Edited: Wayne King
on 27 Nov 2013
That depends on how they are in your workspace. If you have 20 separate vectors, then just do this.
I'll assume they are column vectors and I'll just create 3 signals here.
s1 = randn(33,1);
s2 = randn(33,1);
s3 = randn(33,1);
Sig = [s1 s2 s3];
Now window them as before:
h = hamming(33);
Sig = Sig.*repmat(h,1,3);
Now take the DFT
SigDFT = fft(Sig);
Obviously, you have to make adjustments for the 20 columns above:
repmat(h,1,20)
for example
Wayne King
on 27 Nov 2013
If you have row vectors you have to make the necessary adjustment. Just convert them to column vectors.
s1 = s1';
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