[sdiy] Wanna help me make up a VCF homework? ;)

[Grant Richter]

>
> http://members.tripod.com/urekarm/synth/eml101_exp_osc_vcf.pdf
>
> There's a differential pair, but instead of having a current mirror  
> on top to sum up the current the OTA way, it's a standard voltage  
> setup (resistors to the top rail), and then that goes into a  
> differential integrator with two caps (I remember seeing one of  
> these on Ian's site).
> Don't think I've seen that design anywhere else.
>

It is a standard analogue computer design with linear multipliers and  
integrators.