SV: [sdiy] QVCO schemo up

[René Schmitz]

Hi Jürgen, Ian and all,

First of all: Ian thats a great little circuit.
I'll have to try that one.

JH. wrote:
> The stupid diode biasing system of the 13700 forces
> the common mode input voltage to some positive value,
> which means the resistor that feeds the input signal
> draws a hefty bias current, and unbalances the input.
> So you have to set the offset trimmer to an odd value
> even if you'd have a perfect OTA.

Does this also occur if the impedances at both terminals are
equal? To me the situation is similar (or rather worse) as
with input current on bipolar opamps. (And I have to admit that
I have never used the 13700s linearisation...)

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159