Removing DC component at 0 HZ from acceleration data after fft
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Adam Levschuk
le 29 Mai 2020
Commenté : Nidhi Singh
le 11 Fév 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 commentaires
Ameer Hamza
le 29 Mai 2020
If subtracting mean does not work, then it might be some other frequency?
Nidhi Singh
le 11 Fév 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?
Réponse acceptée
Ameer Hamza
le 29 Mai 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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