LFO -> trigger

[Paul Perry]

At 03:44 AM 23/08/98 -0500, Yoshiki Ohmura (Yoshi) wrote:
>What kind of circuit do I have to build to convert the LFO signal into a
>trigger/gate signal?  Are there any schemtics out there?
>
What sort of LFO have you got?
An easy thing to do is just run the lfo to a comparator.
When the lfo voltage is above the comparator set point, it is ON,
and off when it is below.
This will be enough to trigger whatever you have, the only problem
being that the 'trigger' might not be at the right point of the lfo cycle.

Indeed, you could make a "window comparator" and then you can choose the
part of the
lfo cycle that it is on.... but, there is the second unwanted output on the
downside 
of the lfo.... but, if you run the output into a flip flop arranged as a
divide by
two ckt then you can throw away every second one (or, for that matter, every
odd one,
which gives full ability to select where on the lfo the trigger comes from).

There is a 'window discriminator' ckt on p669 of the 2nd edition of Horowitz
and Hill
"The Art of Electronics"

paul perry melb aust