OTA in transistor level

Even i can read and understand the circuit, may I ask you, what is a "Transistor based OTA"?

Operational Transistor based Amplifier?

So there are non transistor one available if such name is used but hardly to imagine what those are based on. As far i know a elctron tubes were used at first to build such and later a magnetic amplifiers also were used to build op-amps as replacement for tubes especially in computrs and digital equipment. Now we use transistors so what are rest of them based on?? Some variable reactors ?? Such as varactor diodes or mos capacitors or maybe on electrooptical things , a microvave negative dynamic impedance diodes can also be used as active devices to build hf versions of op-ams but i never hear any rumours about existence of such said devices.

Right, but anyway i dont like circuits taken from IC developers which are hard to implement with to92 transistors. Sorry JonTour

It’s just an OTA in transistor-level

operational transconductance amps...i use them in lots of things!! (old ones are ca3080' ca3082' ...modern ones are 13600/13700) of course before those people were using BJTS to make them...it sure would be nice to have 13700s in here!! or really even just any non discrete voltage controlled amplifier!! ssm2164....etc are modern equivs of older otas