circular interpolating scanner

[jhaible]

> While the Hammond Chorus uses a circular scanner, that's somewhat
> deceptive -- the scanner inputs are connected mapping back and forth
> across a line.  Specifically the delay line.  So there's no barber
> pole effect going on there or anything like that.
> 
> A circular scanner would really win for waveform generation; the
> waveform just rotates through 360 degrees with no glitch for a
> sawtooth reset.  I'll suggest that a circular scanner with voltage
> controlled transition shape and through-zero FM would be a mighty
> impressive VCO module.  Hmmm....
> 
>   -- Don

I think the Hammond circular scanner with "mapping back and forth"
can be emulated with a linear scanner of *half* the length and triangle
(not saw) input.
BTW, I rarely use my scanner with saw input even for waveform generation.
I triangle has prooved a much more effective source. Of course the sliders
do not represent the waveform then, but you rather draw the transfer
courve.
Think of a Fuzz box with graphical input for the clipping function. You
normally
drive it with a low harmonic content input wave, like sine, or triangle (or
electric
guitar).

JH.