> 	I need to find the transfer function of this filter, whats the
> topology name? A more detailed picture can be downloaded from
> www.janso.com.ar/filter.jpg

I'm not sure there is a specific name for this filter. It seems to me to be
a combination of five rather independent filters: the three opamp active
filters, plus the two passive filters between the opamp outputs (low
impedance) and the opamp non-inverting inputs (high impedance).

For a quick transfer function, I'd do a simulation. If you need it in math,
you can calculate the five individual transfer functions (they are not too
complicated, it seems) and multiply them. I think they are decoupled
sufficiently (by the opamp outputs and non-inverting inputs) that you can
consider them independent.

Gerhard
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