Digital Frequency Shifter (was Info requested on EMS Phase)

[Scott Gravenhorst]

Well, I've had this one zany idea for a while now that I've still yet
to try...  Imagine a PLL, but in the loop is a digital circuit that
can prevent individual transistions each time it is clocked by another
in put source (square or pulse).  The phase detector would then force
the PLL's VCO to run higher in freq to compensate for the missing
transitions.  I believe that the frequency at which this were done
would be added to the PLL VCO's frequency.

Well, it's just an idea at this point.  I think the special loop
circuit would have to involve some flipflops.  Needs more thought, I'm
sure.  Just an idea.  I'd guess it would have some jitter and
portamento, but who knows what it would sound like.

I certainly don't know if this would qualify as a 'good' idea ;-)

On Wed, 1 Apr 1998 21:39:16 -0500 (EST), media at mail1.nai.net wrote:

>>P.P.S.  Anyone out there know of any good digital frequency shifter
>>techniques? I'd like to work on making Csound do this, but apparently the
>>Hibert transform is difficult to implement in a successful manner digitally
>>for this effect.
>
>I'm also curious to hear this.  Not that I have any plans at all whatsoever
>to build by own digital gear, but I have numerous digital gizmos that do
>pitch shifting but not a single device that does frequency shifting.
>
>PEACE OUT :)
>MARK

-- Scott Gravenhorst