Filmscanners mailing list archive (filmscanners@halftone.co.uk)
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[filmscanners] RE: Density vs Dynamic range>AUSTIN (2a)
This is nonsense. A steady DC voltage contains an amount of information
equal to log2 n, where n is the number of different DC voltages that can be
distinguished by the receiver. It conveys this information even if it
remains unchanged for a million years. This information is exactly what is
displayed by a DC voltmeter.
If you think this information is useless, try capacitively coupling the
output of the CCD in a scanner, to eliminate the DC. You'll of course find
that the scanner becomes useless, because it can no longer distinguish
between an all-white target and an all-black target.
--
Ciao, Paul D. DeRocco
Paul mailto:pderocco@ix.netcom.com
> From: Anthony Atkielski
>
> But samples are not signals, and DC is not a signal. A current or voltage
> that does not vary (i.e., DC) carries no information, and is thus not a
> signal. All signals are AC. More precisely, all signals vary
> over time; DC
> does not vary over time; therefore DC and signals are mutually exclusive.
----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or
body
|
