1 Jul
2006
1 Jul
'06
2:42 p.m.
Philip Pemberton wrote:
Don Y wrote:
You don't care about the DC bias... the image will "self center".
And, consider the persistence of most 'scopes... 20KHz would
be more than adequate for a "sweep rate".
Sound card sure seems easier! :>
Build a WAV file and just have it "play" endlessly.
I'd have thought the AC coupling hardware would have caused problems
with that, and you'll have a maximum frequency limit of about 20kHz due
to the low-pass filters on most sound cards. And I doubt the parallel port would be fast enough.
Best plan would be a
pair of DACs, a counter and a 16-bit EPROM (or a pair of 8-bits).
Program the ROM with the pattern data, hook up a display and have fun.
Could even add a few more ROMs and have colour output and/or intensity
control as well.
Heck, the simplest DAC is a bank of 20 resistors (R-2R ladder). Cheap
too - a penny a resistor, total cost of 20 British New Pence. I don't
think ADI or Maxim have anything cheaper...
The "problem" here is you can't easily change the "display".