The Magnus phase shifter

[Bjorn Julin]

>    http://home.swipnet.se/cfmd/synths/schematics/

>Wow, that's a very nice idea.  I like it.

>A couple features I noticed: First, it can do thru-zero frequency PM.
>By that I mean if you shift the phase backwards quickly you can
>briefly take the frequency negative.

The ViBrAtO effect!!! ho hum!

>Secondly, you can put a number of these in series to do more than
>360-degrees of phase shift.

Not only that, as i did in my PM osc,i use phase shifting of
squares and saws of lower and higher octaves to create
a sort of additive oscillator. Some of the waves does
sound really strange.

>(Ummm, I'm thinking a couple errors crept into the schematic.  >Perhaps the 
>comparator's input are swapped and the resistor values >aren't quite right. 
>  Also, since the circuit is really dependant on >the power supply voltage 
>it would be a good idea to specify that. You want the comparator output 
>transition to exactly compensate for >the sawtooth reset, right?)

It dosent matter you can swap either input, it just shift the phase.

>This circuit is almost the same as the Chroma sawtooth mix.

>Quick description: The Chroma has a comparator, positive input
>grounded, negative input has an equal mix of sawtooth and the PWM
>control voltage, and the result is a resistor mix of the comparator
>output, the PWM control voltage and the sawtooth.

The Chroma uses offset voltages on the + input and
to the summing mixer.

>But the Chroma mixes in twice as much sawtooth because the goal isn't
>a phase shifter but a mix of the original sawtooth and the
>phase-shifted sawtooth for a thicker sound.

Actually when i run Magnus shifter and the Chroma the end
result is the same. Functionally I dont se any difference
between them. The design difference is that Magnus is a
+- 5 volt and the Chroma is a 0 to +5 volt.
And Magnus use a different aproach to DC rejection then
the Chroma does , Both cirquits are capable to do PM.

The ViBrAtO effect!!!

BJ

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