Hi Florian,

> > I suspect
> > the EXOR one, the switch in position 3, will probably be the most
> > useful (I suspect it will give the most usable voltage out of the
> > filter).
> Hmm, I had the best results with 2 (complex dig. network).

I took my own (implied) advice and re-read the datasheet more
carefully over lunch, and realised that my 'suspicion' here was
indeed going to be wrong! Yes, it seems the 'complex digital network'
ought to be best.

> I will have to check the Highspeed VCO in the voicecard of the old
> Doepfer Sound Sampling System. This worked really perfect.

From Dieter's comments on this, I think I understand how it helps to
have a 'two-stage' filter, with a wide bandwidth for 'capture' and a
much lower one for 'lock' - how this works out with an A-171 will
require a little more thought. If I come up with anything useful,
I'll let you know.

Tim