Bear in mind that the series resistance of the sampling switch (6k at
5V) and the value of the hold capacitor (51.2pf for a '76) will band
limit your signal to under 500khz.
However, with an external fast sample and hold, one could digitize video
at a 50khz rate (3 samples per video line). By sampling progressively
later in the line, one could acquire a 640x480 60Hz video frame in 3.8
seconds. (A fully analog version of this technique was used back in the
70's to convert full speed video to the 15Hz line/7.5S frame of slow
scan television used in the amateur radio bands (TV in a 3khz BW)).

"Sean H. Breheny" wrote:
>
> Hi Don,
>
> For certain methods of accomplishing reconstruction, you are right, but I
> don't think that is true in general. You can take any signal bandlimited to
> delta_f, sample it at 2*delta_f, and reconstruct it from the samples. It
> doesn't matter what the center frequency is, or whether it is periodic, as
> long as it is bandlimited. So, for example, you could have a signal which
> filled the entire band from 0.9 to 1.1 MHz, sample it at only 0.4
> Megasamples per sec, and reconstruct it from that, as long as you had the
> additional piece of info that its center freq was 1 MHz.
>
> Sean
>
> At 07:41 PM 2/16/01 -0800, you wrote:
> >Hi,
> >
> >The signal must necessarily be periodic for this to work....
> >Lets not forget that restriction!
> >
> >Cheers,
> >Don
> >
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