[sdiy] linearize OTA for VCF?

[jhaible at t-online.de]

Jim Patchell schrieb:
>     The best (clearest) drawing I have is at
> http://www.silcom.com/~patchell/jp2rest/dualvco.pdf
> 
>     There is only 1 LM13700 on the page, so, it is pretty 
> easy to 
> locate.  I used a CA3046 for the current sources, and 
> they also double 
> as the inputs.

Nice circuit. And yes, you got rid of *all* the resistors,
reproducing the "classic" method. No doubt that this works fine.
Is it an improovement over National's method ? Extended linear
range ? Lower offset voltage modulation ? Any other improovement ?

JH.