Bode Barber Pole Phaser

[Haible Juergen]

I'm making the following comments off-hand (I have not read the text of that
patent yet, and I see Magnus will recommend me to do that soon (;->) )

	>  The Bode's 'Barberpole Phaser' or infinite phaser uses a
frequency
	> shifter and a standard phaser in a feedback combination. 

Not a standard phaser. Only the delayed part (all pass filter) of a standard
phaser. 

	  > The phaser
>   > frequency nulls are shifted up and down through the frequency shifter.
> 
Cannot be. The FS range is a couple of Hz or less. You would not
notice a shift of notches of that amount.

So when the FS does not shift peaks and notches of a standard phaser
around, what does it do ?
I'd say frequency modulation with a sine wave is equal to a phase modulation
(with different index, of course), so the the FS's part is that of a time
variant
*phase shifter* (not "phaser" (;->)). Addition (or substraction) with the
time
invariant (but frequency dependent) phase shift of the fixed all-pass
filters 
will give the phase addition / phase cancellation you need for a phaser's
peaks and notches. As you don't mess with the frequency dependent
all pass part anymore, the *relative* location of the notches will be
constant
(unlike an ordinary phaser, where it's compressed and dilated). These
notches and peaks are then cyclically shifted by additional 0 ... 360
degrees *phase* modulation from the FS branch. Which will result in
a motion of the peaks and notches along the frequency range, of course,
but in a different pattern, and cyclical.

I'd say the FS's local frequency takes the LFO frequency part.

Does this make sense ?

JH.