[filmscanners] RE: Film resolution - was: Re: 3 year wait

["Austin Franklin" <darkroom@ix.netcom.com>]

> >That is not correct.  Partial reconstruction, only frequency,
> yes, but not
> >complete by any means.  You do not get any guarantee of accurate
> amplitude
> >reconstruction with 2xf, nor do you know what the waveform was.
>
> As I understand the Nyquist Theorem, 2f is the _minimum_ frequency needed
> to reconstruct the waveform. Are you saying that the theorem has been
> disproven, or that technical considerations make it impossible to achieve
> the theoretical results? Or something else?

I am saying that sampling at the Nyquist frequency (2f) only (reliably)
gives you the frequency, not necessarily the amplitude (it can, if your
point sample happens to hit the top or bottom of the wave), nor what the
shape of the waveform was.

Austin

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