[sdiy] Is a 'fake' Scope Risky?

[Curtin, Steven D (Steven)]

This works fine- around here we've even just used Sound Forge or Cooledit
and recorded audio into it using a sound card for signal testing.  It's like
having a built in storage oscilloscope.   The other limitation is that the
inputs to sound cards tend to be AC coupled, so you can't measure stationary
or slowly changing voltages.  It's also not as interactive as a continuously
updating analog scope.

> Fake Scope: I don't have a 'real' oscilloscope anymore, but I have a
> roundabout/poor man's version that has worked in the past (being very very
> careful of course). It is limited, in that I can only measure signals that
> are within a line-level audio input. What I do is first check the signal
> with a meter to see if it's within what I can connect to my mixer, then I
> route that into my computer with an oscilloscope program - it has a pretty
> accurate measurement if I calibrate the mixer gain first. Am I a complete
> idiot for even attempting this? It has worked for me in the past,
> especially
> for calibrating waveshapes and such.
> 
Steve C

-----------------------------------------------------------------
Steven Curtin  
Agere Systems (formerly
Lucent Technologies Microelectronics)
ph: (732)949-4404   fax: (732)949-6711
http://curtin.emf.org
sdcurtin at agere.com
-----------------------------------------------------------------