[sdiy] more pitch shifter thoughts

[PRCamann at aol.com]

In a message dated 1/10/2005 1:01:56 PM Eastern Standard Time, 
music.maker at gte.net writes:

> Being a 4046 PLL kind of guy, I have wondered about stability and tracking
> when doing this.  I have a PLL module that uses a divide by 12 counter in
> the loop and it works just fine.  But the MK50240 has a range from divide
> by 239 to divide by 478.  
> 
> What kind of problems, if any, will there be with such large counters?  
> 
> I would think that proper VCO capacitor selection is important.
> 
> Over/undershoot?  
> 
> Does a large counter affect lag very much?  
> 
> My own circuit has adjustable damping for the loop filter and allows me to
> adjust it so that frequency changes are so immediate that I do not hear any
> over/undershoot or lag.  But then, my PLL has only a divide by 12 counter
> in the loop.
> 

Per my earlier post, I built this circuit in the late 70's.  Used it with a 
trumpet as input, also with an old Bee Gees Music Maker keyboard as input.  
Worked fine.  No noticeable lag.  I think I used the capacitor values from the 
frequency synthesizer circuit in the old RCA app notes for the 4046.  

Paul Camann
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