oscilloscope virtual instrument

[brad sanders]

>Can anybody recommend to me a source for a kit or a PCB design for a
>virtual oscilloscope (digital store scope hosted by a PC)?

What bandwidth do you want? I wrote some software in TP6.0 to control
a parallel port data acq. device based on a very simple ramp ADC. It
can sample eight channels simultaneously, and accuracy is limited by
CPU I/O speed and sample time (ie you take longer for each sample, you
get better accuracy). It works fine to about a 20KHz sample rate. The
main feature of this is it preserves phase information, and it's dirt
cheap (555 ramp generator and two quad comparators).

The same ML core routine (it's incredibly simple) could be used to
fetch "regular" parallel data from the port at up to 2Mhz (at least on
my 486DX2/160 system). Connect a suitably fast A/D to the parallel
port and you got a single channel 1MHz BW scope. 

Or, you could but the $99 thing from radio shack. I think it has a PC
interface. Or, you could use your soundcard (up to 48KHz sample rate).
I do this quite often.


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