PAiA VCO

[patchell]

    I just took a good look at the circuit.  I also redrew it , which I find
helps a bit.  But after I looked at it I saw something else that I find
curious.  In the FAQ it said it was using the diode in the linearizer for a
temp sensor.  I don't think so.  In order to use a diode as a temp sensor, you
need to maintain a constant current through it.  The way the circuit is set
up, very little if any current will be flowing through that diode.  In my
opinion, the tempco would be generated by the temperature dependence of Gm of
the transconductance amplifier.  Even if the diode were forward biased, it's
tempco would be canceled out the tempco of the Gm.  I depend on this for my
own electronically compensated exponential converter.

    Time to break out the superstrip, I guess.  I am going to get to the
bottom of this puzzel.

Ian Fritz wrote:

> Yes, they seem not to understand how tempcos work. LOL! They repeat the
> silly old dodah about how a tempco can only compensate at one temperature,
> etc. Very disappointing.
>
>   Ian
>
> ----- Original Message -----
> From: "René Schmitz" <uzs159 at uni-bonn.de>
> >
> > I find the explanations on the FAQ page confusing, tempcos must be
> > proportional to T in order to compensate for 1/T since that cancels out
> > when you multiply.
> >

--
 -Jim
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