MOTM

Larry wrote:

I have it on a freq. meter right now. Of course, it is designed to not
oscillate at very low frequencies to emulate the 904A (as I 
understand it having never owned or even seen a 904A). So, I am 
starting with 220Hz. I am increasing the input in even one volt 
intervals:
220 Hz
438 Hz
889 Hz
1804 Hz
3591 Hz

Obviously, VCO tracking would be:
220
440
880
1760
and 3520

*******************

Very interesting.  Thanks for the detailed info, as I have been 
curious.  

I just stuck a frequency counter on my Synthesizers.com Q150 ladder 
LPF after reading your reply.  The results were:

220
440
882
1755
3456 

Like your filter, this one can be tweaked (though not internally) for 
greater accuracy in particular ranges.  It does have a nice sweet 
sine.  Interesting to compare.

johnm