Hi, On 2019-11-28 21:18, Joseph Gwinn wrote: > JD, > > I'll have to think about it, but I will mention that with batch > processing using window functions, it's common to precede the FFT using > a simple FIR filter to eliminate the low-frequency energy (due to > clutter, DC leakage/offset et al), the problem being that the FFT alone > may not have sufficient rejection to prevent low-frequency energy > breakthrough. > > An alternate approach is to compute the mean of the windowed data and > subtract that mean from all samples in the window before computing the > FFT. In analog terms, this is like a big coupling capacitor blocking > DC.
You also wants to remove the slope between the two sample end-points, or else that slope represents an in-phase sawtooth function. A window-function tends to do that. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
