EMS Pitch 2 Voltage

[Martin Czech]

Huuuh, very hard to figure out these drawings.
AFAICS the pitch converter works with a monoflop,
ie. pulse density modulation according to input frequency.
Should give some ripple, even after integration.

Ok, there is a "tracking filter" , obviously a diode
cascade type lowpass for the input, but how does it track?
Can`t see any connection to the pitch voltage,
also not on the principle operation diagram.


What machine uses this P2V converter?
Any experiences out there?

Yesterday I found a National PLL app. note, where they claim
this would be much better than 4046. 
They use current spikes to charge an integrator, less
ripple. And also the current spikes are scaled with
frequency, thus very short response time.
There are scope shots, so must have worked.
Provided with an ideal pulse train input they claim
that this is a very good P2V converter.

Unfortunetely I've forgotten the app. number.
It is in the National app. book I mentioned earlier,
look under PLL.

m.c.