[sdiy] Temperature Compensated Exponential Converter Using SSM2164

[David G. Dixon]

> >> It bears noting that the temperature compensation is not perfect, and
> >> deteriorates rapidly as control voltages go above 0V (i.e., the sum of
> >> square errors gets geometrically larger with increasing control
> voltages
> >> above ground).
> >
> > I made the classic mistake of failing to non-dimensionalize my errors.
> When
> > I divide the square error by the square of the desired value, I find
> that
> > the tempco gets progressively worse the further out the control voltage
> is
> > from 0V, on either side, as expected.  High-frequency compensation may
> still
> > be necessary in this circuit because of this fact.
> 
> How do you know which calculation is correct and what the correct way
> of understanding the results is?

They are both correct.  However, I was interested in the degree of relative
error, not absolute error.  Missing the next octave by 1 Hz is no big deal
if your target is 1760 Hz, but it is a very big deal if your next octave is
55 Hz.  Capiche?

> Also, I see no point running my synths at 5 degrees Celsius.

It depends.  You could be playing an outdoor glitch festival in Oslo or a
winter noise gig in Reykjavik.  Hey, it was late, and I was in a hurry!  Why
don't you enlighten us with your analysis, D?