[sdiy] Oscilloscope question

[Andre Majorel]

On 2010-02-21 11:39 -0700, Ian Fritz wrote:
> At 11:18 AM 2/21/2010, Jerry Gray-Eskue wrote:
> 
> >A PC with a sound card will work, just about any of the audio
> >recording software could be used.
> 
> Provided you can find (or afford) a sound card that goes down to DC.
> These days most are AC coupled.

If you don't need great precision, you could "chop" the gain
between +1 and -1 with a four-quadrant multiplier (or maybe just
an op amp and a FET ?) and a bipolar square wave.

One could even record the square wave on another channel and
automate the demodulation. If the computer itself generates the
square wave, you get one input channel back but need to adjust for
I/O latency.

-- 
André Majorel http://www.teaser.fr/~amajorel/