Re: [CAD_CAM_EDM_DRO] Oscilloscopes

> I've been wondering for some time about how good the various free and
> shareware programs are which allow you to use your PC as an oscilloscope.
> They take input through the soundcard or joystick port and some seem to
> offer quite advanced options. Whilst I've downloaded a couple of them
> (oscope.exe, scoper.exe ) and run them 'dry' to see what the displays are
> like, I've never yet plucked up enough courage to hook 'em up to anything
> serious.

A digital oscilloscope is only as good as digitizer... using a
soundcard or (worse) joystick port means you will be limited to things
of audio frequency or less. Most soundcards will sample up to 48khz.
That means that the highest frequency signal you could monitor with
such a setup would be half of that, or 24khz. Trying to look at a
higher frequency may even give an incorrect picture due to a sampling
illusion called 'aliasing'.

Even several-hundred dollar hardware accesories designed to turn a pc
into a software-based oscilloscope often do not have a robust filter
design to prevent aliasing under all modes of operation.

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
(617) 629-9830 home (temporary), 253-2606 MIT