Removing DC component at 0 HZ from acceleration data after fft
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Adam Levschuk
on 29 May 2020
Commented: Nidhi Singh
on 11 Feb 2022
Hello,
After i compute the FFT of my acceleration data (Fs = 50 Hz) i am getting a large spike at 0 Hz (the leftover DC component). I have tried subtarcting the mean and detrending my data (detrend(X,2)).
Here is my code:
n = length(acc(:,1));
accX_fft = fft(acc(:,1),n);
PSD = accX_fft.*conj(accX_fft)/n;
freq = linspace(0,50,length(accX_fft));
L = 1:floor(n/2);
plot(freq(L),PSD(L));
The amplitudes of the frequecieis i want to visualize are already very very small, so the spike at 0 Hz is really distorting the view.
Id appreciate any reccomendation on how to get rid of this spike.
2 Comments
Ameer Hamza
on 29 May 2020
If subtracting mean does not work, then it might be some other frequency?
Nidhi Singh
on 11 Feb 2022
I am having the same doubt. If subtracting the mean doesn't work, than can we use high pass filter here with fft graph?
Accepted Answer
Ameer Hamza
on 29 May 2020
As described here: http://blog.originlab.com/how-to-remove-dc-offset-before-performing-fft try using a high-pass filter to remove very low frequencies from your signal. See highpass(): https://www.mathworks.com/help/releases/R2020a/signal/ref/highpass.html
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