[sdiy] Temperature Compensated Exponential Converter Using SSM2164

[Tim Parkhurst]

2009/8/29 HOSHUYAMA <houshu at muj.biglobe.ne.jp>:
> Hello List,
>
> I developed a new style temperature compensation method for
> exponential converter using SSM2164.
>
> http://houshu.at.webry.info/200908/article_1.html
> http://houshu.at.webry.info/200908/article_2.html
> (Japanese blog, but, comments in the schematics are in English.)
>
> On a simulator, change of frequency is less than 1% from 0
> to 40 degrees in C, over 10 octave.
>
> On my breadboard, it showed very good temperature
> stability.  Even when I touch the chip, frequency change was
> less than 0.2%.
>
> Best,
>
> Sam HOSHUYAMA
> Saitama, JAPAN
>

Very impressive Sam, but does this work significantly better than
using a tempco resistor with the 2164? This is how the Mankato VCF is
set up, but I have to admit I've never really measured the temp
compensation (especially since it's a VCF and not really sold as a
VCO).

Tim (under compensated) Servo
-- 
"Sire, the church of God is an anvil that has worn out many hammers."
- H.L. Hastings