Korg Poly800/EX800 Users

if this is being discussed, any plans to add pulse width?
(to original DCO)
eg: if the square is produced by a comparator, varying the 
input compared to will vary the pulse width. maybe 
simething similar is possible here?

--- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@...> wrote:
>
> Gordon,
> 
> I want to be able to digitally control the oscillator variation of DCO2. Digital 
> control also might mean using a D2A or use an analog control. Or even a digital 
> pot.
> 
> But the goal here is to be able to vary the frequency of DCO2 which gets its 
> "master" rate from the master clock. The master clock will continue to be sent 
> direct to DCO1. And the MG and joystick bend will also continue to vary the 
> master clock rate (thus giving both DCO1 and DCO2 the same MG and joystick bend.
> 
> So I want to continue to use the original Poly master clock but want to insert a 
> new DCO2 "detune" that has far more frequency variation and far more granular 
> control than the current detune.
> 
> I seem to remember from my electronic engineering classes (that would be 15 
> years ago now) that a phase locked loop (4066?) might be the way to do this. 
> Does anyone have experience with PLL's for generating frequencies that are 
> slightly varied from the input master clock?
> 
> Mike
> 
> 
> 
> 
> ________________________________
> From: Gordon JC Pearce <gordon@...>
> To: korgpolyex@yahoogroups.com
> Sent: Mon, July 18, 2011 2:17:47 PM
> Subject: Re: [korgpolyex] DCO2 detune
> 
>   
> On Mon, 18 Jul 2011 00:55:06 -0000
> "korgpolyex800" <korgpolyex800@...> wrote:
> 
> > Can anyone suggest a way that I could produce a slightly offset oscillation 
> >based on a master clock source? And that slight offset could be adjusted using 
> >digital or analog signal voltage technique?
> 
> Not easily, but you could use a crystal oscillator with a varicap diode to pull 
> it a few kHz.  I don't know if that would get you the range you're looking for.  
> Some radios use a transistor and a capacitor to shift the CPU clock a bit.  That 
> way, if a harmonic of the clock oscillator will cause interference to a 
> particular channel you can move it out of the way.  I'll see if I can scan in 
> the relevant page of a manual that shows this - I know the Motorol MC Micro has 
> this, so if you find a PDF you can maybe do something with that.
> 
> If you really wanted to go nuts with it, you could use a DDS chip.
> 
> Gordon MM0YEQ
>