On Thu, Apr 1, 2010 at 11:11 AM, Matteo Sisti Sette matteosistisette@gmail.com wrote:
Matteo Sisti Sette escribió:
Oh no, maybe not. I read your explanation more carefully and of course, the non-perfectness of the interpolation process (i.e. its non-zero frequency response in the stop band) is responsible for the persistence of attenuated copies of the original spectrum at multiples of the original sampling rate, which then appear aliased into the passband when the signal is sampled again at a different rate.
This is what's going on when discontinuities in the interpolated signal cause noise at high frequencies, isn't it?
Yes, that's my interpretation and explanation of it. It works out nice and linear in the spectral domain *if* we can make that intermediate step with the Dirac-delta comb which copies the spectrum. Then, *all* the deviations in the reconstructed signal come from the places where the spectrum does not match the ideal response.