[sdiy] What is a quadrature oscillator good for?

[jhaible]

> Sure, but that's a correction that adjusts the trigger points and
> therefore only works averaging over multiple cycles, right?  Or am I
> confused?

No, that's right.

> I'm thinking of a specific case where the VCO is sitting at 0 Hz, then
> you nudge it to a very slightly positive frequency for a tiny bit, and
> then nudge it to very slightly negative frequency for another tiny
> bit, then back to 0 Hz, not moving more than a fraction of a cycle
> total.
>
> That's a weird and difficult case, certainly, but handling this case
> with the quadrature phase relationships precisely intact was a goal of
> mine.  I could not find a way to implement a triangle core that kept
> the phase relationships intact in this situation, so that led me to
> the trapezoid core.
>
> Does this ever come up in real life?  Sure, if you want to accurately
> model the position of a freely rotating object.  That's one of my
> goals (though it might not be anybody else's goal).

I clearly see applications for this: If you want to _stop_ a panning
movement, infinite phaser, or simply put a FS into zero shift
without a bypass switch.
But won't you have problems with leakage here, even with the
trapezoid core?

JH.