Vector Imagery

[Tim Shoppa]

Philip Pemberton <philpem at dsl.pipex.com> wrote:
> 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.

Non-existent problems.

I've been doing this since the 70's and AC-coupled scopes are just fine
as long as you don't do any horribly baselined stuff. And with regards
to rate and CPU speed, I never had any problem using CPU's that were
realistically a tenth of a MIP or slower :-).

If it's just a half-dozen letters then there's dozens of ways to
implement it (some of them COMPLETELY ANALOG.)

My favorite thing to put on a X-Y scope is in fact the output of
an analog computer.  See Paul Horowitz's Lorenz equation integrator
for a wonderfully chaotic example:

  http://frank.harvard.edu/~paulh/misc/lorenz.html

I built this, added some knobs to twiddle the parameters,
and hooked it up to a 10" X-Y display and am very happy :-).

Tim.