Re: Beagle Bros and Wonderful disk drive noises

[jav@os2bbs.com]

In <31CA02BB.453821FB@swec.com>, "Carl R. Friend" <carl.friend@swec.com> writes:
>A.R. Duell wrote:
>> 
>> 
>> Seriously, there was a thing called a 'flying spot scanner' used to
>> transfer frames of cine (movie) film to television. It used a CRT with the
>> light from the screen being optically focused onto the the frame of the
>> film. A single photodector (originaly a vacuum photocell or
>> photomultiplier) recorded the ammount of light that passed through the
>> frame. The electron beam was scanned over the CRT screen as normal (at a
>> constant intensity), and the output of the photocell was an electronic
>> representation of the image on the film.
>
>   This sounds amazingly like an electronic equivalent to John Logie
>Baird's mechanical apparatus which was a very early form of television.
>
>   Posts like this make me realise that no matter how drastically
>things may change (68000 CPUs vs. spinning wheels with lenses) they
>have the power to stay the same.

Flying-spot scanners were (probably still are some places) used routinely
to produce the maps on analog radar screens.  A negative of the map 
(transparent lines and lettering on an opaque background) was scanned 
radially to match the radar sweeps.

     --------------------------------------------
     -----  John Varela     jav@os2bbs.com  -----
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