AW: constant phase shifts

[Haible Juergen]

	> Hmm... quadrature saw/tri oscillators isn't common, are they?
	>
	> Has Juergen any thougths on this?

Variable phase shift of a single VCO output should work
with the PLL method. Or in the case of sine waves start
with a quadrature VCO ( produces sin(wt) and cos(wt) ),
and get your arbitrarily phase shifted sine with two additional
VCAs (with gain A and B):

sin(wt + phi0) = Asin(wt) + Bcos(wt)

But I don't think this is elegant. If you have one single frequency,
why not use a simple VC all pass filter that tracks the VCO 
frequency ?

Shifting *all* frequencies ... well, that's Hilbert Transform, Dome Filter
stuff.

The original question was about "phase shifted" *triangles*, however.
I don't think that the same amount of *phase* shift is really what was
wanted. At least, if you want to preserve the triangle waveform.
So what about a constant *delay* time for the whole waveform?
A VC-BBD that tracks the VCO frequency, maybe ?

JH.