Doepfer

Hello Neil

Thanks for the hint.  I did some further experiments the last hour, and 
can confirm, that the CP1 is more stable on a only slightly varying 
master frequency, but it would not cover a wider frequency range (more 
than an octave) of the input signal.

For varying frequencies I get the best results with CP3. In the range of 
the input signal between 80 and 400Hz I get up to two and a half octaves 
- but for the Din-Sync clock multiplication I will have input signals 
between 10 Hz and 100Hz. I tried with various filters (esp. the 
slewlimiter), but I do not get a satisfying range with this low input 
frequency.
I can make it track fine, if I send an additional control voltage to the 
PLL's VCO and to the VC-slewlimiter, that corresponds to the frequency 
of the input signal. But this will not be available in the case of the 
DIN-Sync multiplication.

I think for my DIY project I will work with a two stage approach.
Part 1 will be counter based F/V converter, which provides a rough 
control voltage.
Part 2 will be the PLL that does the fine tuning.

Nevertheless if anyone can provide reliable settings for low frequency 
syncing with an wide range, any help is appreciated.



 > you are looking to do a x40 multiplication which using the A160/161 
is not going to work
 > (sorry you clearly know this already),
Yes ;-)
It won't work only the 160/161 or with a standard 160/161 . But there 
are several approaches to achieve it:
The first is: use logic gates, that read decimal 41 = binary 101001 from 
the output of 160 and send the output to the reset.
The second is: take the 1/8 signal from the A-160 and trigger with it 
the A-161 and use the step 6 as reset. This requires a modified A-161 
that has been extended with a separate clock input.

But in fact, I want to use the A-100 system experiment only with the 
PLL. Therefor it is not necessary to have the true division factor. The 
final device will be a custommade standalone unit, where the divider is 
made from a CD4520 and two ANDs.

Florian

Am 23.04.2015 um 08:56 schrieb Neil Kagan blinkenlicht@yahoo.com 
[Doepfer_a100]:
> I don't know if there is an 'ideal' setup. Certainly CP1 seems more 
> stable than the other two, as it locks at harmonics. I think you might 
> find that it is going to be a process of just trying things until it 
> works... One thing I did notice is that you are looking to do a x40 
> multiplication which using the A160/161 is not going to work (sorry 
> you clearly know this already), so would the VC frequency divider be a 
> better option?