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RE: filmscanners: RE: filmscanners: pushing dynamic range on the nikon 4000ed--What is Analog Gain




> BTW, is the amplifier stage always implemented between the CCD
> analog output
> and ADC input ?

Yes, as it is the only analog place in the signal path!  The gain is
typically used to calibrate the output range of the CCD with the input range
of the A/D...and typically just to accommodate the light output of the
bulb...it's for light off, then light on.  It would be nice, and there are
some scanners that do this, but not our type of film scanners, if the gain
was done with respect to the film...if the setpoints were done in the analog
gain, simply because this would give you more "bits" of real data.

> Are there scanner's implementations utilizing digital gain
> (multiplications
> after appropriate digital filtering) rather then in analog domain ?

I don't believe so.  As I said above, theoretically, you would want as much
usable signal to go to the A/D to use the most of the A/Ds dynamic
range...and that has to be done in analog, since by the time it gets to the
A/D, it's too late.




 




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