[sdiy] More infinite-phasing examples

[Scott Nordlund]

> I (once) envisioned using multiple notch VCF driven by ramps (up or down) with
> VCAs to blank (mute) the retrace. The notches could be controlled for bandwidth if you like,
> octave spaced (or other). I think this might sound a lot different than the frequency
> shifted method.
>
> It would be really complex, but maybe not any more complex that the frequency shifted method...
>
> H^) harry

I hate to suggest something digital, but this approaches (or exceeds) the limit of what you really want to be doing in the analog domain.
Digital frequency shifters aren't terribly complicated; certainly the thru-zero quadrature oscillator is a lot easier to do. It's no picnic to approximate a Hilbert transform from scratch, but other people have done the work already. I've enjoyed putting multiple frequency shifter based "barber pole phasers" in series, with a different modulation rate for each. It starts sounding like a very intense filter bank type effect once you get to about 4 or 8.
And with FFTs you can get arbitrary notches almost trivially...