Hi,
I am analyzing a signal using FFT to obtain its frequency spectrum. Raw data is shown below.
The machine should measure at a frequency 0.316 Hz.
Code spectral analysis:
x = t2(:,3);
n = length(x);
dt = 3;
fs = 1/dt;
t = (0:n-1)*dt;
y = fft(x);
f = (0:n-1)*(fs/n);
power = abs(y).^2/n;
figure()
plot(f,power)
xlabel('Frequency [Hz]')
ylabel('Power')
grid on
After spectral analysis I end up with two peaks: one at 0 Hz and one at 0.3316 Hz.
If you uncomment the second line you end up with this: a peak at 0.0017 and 0.3316 Hz.
My question is how to interpret the first peak? Has it a physical meaning? I've read somewhere that a large peak at zero frequency means that you have a massive DC offset. What does that mean? And could it be that through discretization the actual value (0.316 Hz) and found value (0.3316 Hz) are slightly different?
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