[sdiy] PC based oscilloscopes

[Tim Stinchcombe]

Thanks to all those who responded to my oscilloscope question - I
particularly like the idea of the digital scope route, which I hadn't
considered before. A quick look around at some second-hand prices though
suggests this will work out quite expensive: scope+GPIB module+GPIB
interface card+software I reckon in the order of £400+£200 (? guess)+£200+
at least £200 = expensive (finding a reasonably priced sw package is likely
to be the killer!). However I may give Telford ELectronics and Stewarts of
Reading a call to see what they say. I've also found someone on s.e.d who
uses a Picotech, so I can pump him for some more gen too!

Thanks again,
Tim

__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk


> 
> 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
> ----  IEE Cambridge Branch: http://www.iee-cambridge.org.uk  ----
> 
> 
>