[sdiy] Interpreting four-pole-w-feedback circuits

[Ian Fritz]

At 09:53 AM 3/6/2008, Aaron Lanterman wrote:

>BUT... I'm bewildered by the four-pole arp patent circuit. The stages
>look inverting (since the opamp-cap-in-feedback is an inverting
>configuration), the four of them in casecade should give total
>noninverting behavior, that's OK... but... it looks to be like the
>feedback loop is POSITIVE. I'd expect the input to either go through
>an inverting opamp before being fed back, or for it to go to the
>negative terminal of the first OTA (so that first stage would be
>noninverting, but the other three inverting, so it would all go
>through with a minus sign).
>
>What am I missing? Where is my thinking going wrong?

Aren't the transconductors inverting?