hey that sounds nearly identical to my new favorite device, a box a friend of
mine has put into production recently, called simply the PLL. it's an amazing
thing.. mine will have CV added soon, and an arpegiator for cycling through
harmonics. it has germainium overdrive circuits built into the mixer controls
and a waveshaper on final output. very musical device!

have a look:

http://members.toast.net/photos/album.asp user=pscottm&album=
schumann%20PLL

also, i just loaned him a doepfer mini power supply/bus board & blank panel
so he can develop one in euro module format. (actually, it'll just be the PLL
'front end' osc control circuit, not the multiplier/divider, or mixer.
-psm



Lindholm" <andreas.k.lindholm@t...> wrote:

> That sounds interesting to me although I don't completey grasap it, but the
> wobbling and inaccuracy in this case could be more advatageous as an

effect

> than a pure VCO it seems to me... when did this module come up on the
> agenda I didn't even know it was something Doepfer had in mind....
>
>
> ----- Original Message -----
> From: "Bakis Sirros" <synth_freak_2000@y...>
> To: "Doepfer_a100 group" < doepfer_a100@yahoogroups.com >
> Sent: Thursday, June 26, 2003 6:06 PM
> Subject: 1 a brief explanation about the uses of a PLL
> VCO.(from doepfer.)
>
>
> > dieter says:
> > "a PLL and it's application is not very easy to
> > understand. I will try to write an explanation and
> > publish it on our web site as soon as we publish the
> > preliminary page for the PLL module (no A-100 number
> > so far).
> > Here is a simplified explanation: A PLL is a linear
> > rectangle VCO with a frequency comparator that
> > compares the frequency of the internal PLL-VCO with an
> > external frequency (master frequency) - e.g. the
> > rectangle output of "normal" A-100 VCO - and makes
> > the the internal VCO frequency equal to the external
> > frequency. Or better said: it tries to adjust the
> > internal frequency so that it becomes equal to the
> > external frequency. The problem is the frequency
> > comparator - even called phase comparator - that
> > generates a kind of a correction voltage that becomes
> > zero if both frequencies are identical. Different
> > versions with different advantages/disadvantages of
> > frequency comparators are available. Some types of
> > comparators e.g. will "lock" even at multiples of the
> > frequencies. Another problem is the time that is
> > necessary until the PLL-VCO is adjusted. It will
> > always take some time until the new frequency of the
> > PLL-VCO is reached (similar to portamento). The time
> > constant of the internal low pass filter (not an audio
> > low pass but a low pass/slew limiter for the
> > correction CV) defines the time until the new
> > frequency is reached. But this time has not to be too
> > short otherwise the frequency of the PLL-VCO will
> > "wobble" around the master frequency. These
> > "disadvantages" lead to additional musical
> > applications like portamento effects or wobbling
> > frequencies according to the type of frequency
> > comparator and time constant of the PLL low pass
> > filter.
> > Another application is frequency multiplication in
> > combination with an external frequency divider. For
> > this the output of the PLL-VCO is processed through a
> > frequency divider (e.g. A-160, A-161, A-163) before it
> > is fed to the PLL frequency comparator. In this case
> > the frequency of the PLL-VCO will be a multiple of the
> > master frequency. E.g if the the A-163 is used and
> > adjusted to dividing factor 5 the frequency of the
> > PLL-VCO will be 5 times the frequency of the master
> > VCO. Consequently frequency division (A-163) leads to
> > frequency multiplication with the PLL circuit. In
> > combination with the PLL low pass frequency several
> > effects can be realized (frequency multiplication with
> > portamento or wobbling). The frequency multiplication
> > can even be used to drive a graphic VCO. If your
> > graphic VCO e.g. has 8 steps (e.g. A-155) and you use
> > a frequency divider with factor 8 in the PLL feedback
> > the output of the graphic VCO has the same frequency
> > as the master VCO. Another application is the
> > generation of pseudo-harmonics (not real harmonics as
> > only rectangle waves are available).
> >
> > I hope this explanation will help and not cause more
> > confusion. I know that the PLL is not very easy to
> > understand.
> > Best wishes
> > Dieter Doepfer"
> >
> >
> >
> > INTERESTING OF COURSE,YES!
> > bakis.
> >
> >
> >
> >
> > =====
> > synthfreak(parallel worlds)
> > athens-greece
> > 1 group owner
> >
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