[sdiy] triangle hard sync

[cheater cheater]

Use the oakley idea then invert?

Cheers,
D.

On Fri, Jul 9, 2010 at 09:43, David G. Dixon <dixon at interchange.ubc.ca> wrote:
> Hey Team!
>
> I'm trying to retrofit hard sync onto triangle-core LFOs so I can sync them
> with gates, triggers, square waves, etc.  I can get the triangle to reset to
> 0V with a JFET across the cap, but I also want the triangle to start in the
> upward direction every time as well.  I can just about achieve it if I put
> sync spikes into the comparator reference voltage input, but the negative
> sync spikes cause the triangle to reverse direction, which I don't want.
> This wouldn't be a problem if the sync source is a sawtooth, but a square or
> a gate signal would always have negative spikes.  I suppose I could add a
> rectifier to eliminate the negative spikes, but that seems too complicated.
>
> I see that the Oakley VC-LFO does what I want, albeit in the wrong
> direction.
>
> Also, I could probably rig it such that the triangle started at its most
> negative point, in which case it would have to go up.  Perhaps I'll look
> into that next (that might be better).
>
> In any case, if anyone knows how to do this, or can point me to a document
> where I could learn about it, I'd sure appreciate it.  I believe that Magnus
> Danielsson had a relevant document, but the link appears to be dead.
>
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