If we look at DFT formula:
N-1
S[kΩ]=Σ S[nT].e^(-j2πkn/N), 0 ≦ k ≦ N-1
n=0
If I'm not mistaking, after we calculate the frequency spectrum,i.e. S[kΩ], the small numbers k, are the low frequency components(harmonics with small numbers), which contain the main part of the spectrum of the signal. And the harmonics with big numbers,i.e. big values of k, contain the detail information of the signal such as fronts.
I'm wondering how to determine exactly which frequency components contain the detail information for the signal, after we do FFT on the original signal, i.e. I need a way to understand which are the numbers k of those components, so I can take their values and work with them?
I hope I have explained it right, because I don't have much experience in signal processing. :smile: