[sdiy] PC based oscilloscopes

[Neil Johnson]

Tim,

One suggestion: hunt around eBay or Stewarts of Reading or somewhere and
grab a Tektronix TDS220 or similar, and get a comms module (RS232 and
GPIB) for it.  Its digital sampling, portable and easy to carry, and very
versatile.  We used them for general lab bench machines, only pulling out
the big guns (LeCroy, HP, etc) if really necessary.

Personally I would avoid PC-based test equipment for many reasons, but
a few are:

1) you pay almost as much for a new PC card, as you would do for a
   2nd-hand Tek scope or similar, and its easier to send off a scope to be
   calibrated than to faff around unplugging the card from your PC;
2) you'll need the PC close to where you are working;
3) you'll need the PC on all the time you are working;
4) PCs generate loads of noise, so not good for being near your bench;
5) if something fails in the input stage, then you're PC goes up in smoke,
   not only destroying your "scope", but also all your files;
6) a scope is more portable;
7) on a scope, the screen and controls are all together, and you can
   operate several controls at once, which you can't do with a mouse;
8) smaller scopes don't have fans;
9) you can't play minesweeper on a scope.

Hope this helps,
Neil

--
Neil Johnson :: Computer Laboratory :: University of Cambridge ::
http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
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