[sdiy] VCO idea

[Ian Fritz]

Charlie --

Well, I mean the the reset portion of the waveform.  The voltage re-crosses 
all the comparitor thresholds so you get very short pulses on each 
output.  You just have to be sure that the S/H's you are triggering will 
not be sensitive enough to fire on these short pulses.  Not a big problem, 
really, but you do have to watch it.  Also the saw must reset cleanly. If 
it has oscillations then these can cross the lowest thresholds and give you 
spurious triggers also.  The "AMS" VCO could give you problems in these 
area, and I would really recommend the updated version on my website, which 
was built specifically for driving S/H circuits through an LM 
bargraph-driver chip.

   Ian


At 06:13 PM 1/13/2003, charlie lamm wrote:
>By flyback I take it you mean when the saw signal goes from its lowest
>voltage (relative to ground) to the highest?  Yes, I guess this could be a
>source of a lot of headaches.  I will know more when I start to breadboard
>this I guess.  Now you guys are getting me really curious about how to
>pull this off!
>
>On Mon, 13 Jan 2003, Ian Fritz wrote:
>
> > The overlap is quite small (~ 1 mV) but might be noticable if you are using
> > the output voltages for signals.  But if you are just using the outputs to
> > fire S/H circuits, i.e., using separate voltages for the signals, then
> > there is no problem. Watch the flyback, though!