I was replacing today some tinypic broken links with local uploads on various online places, and was amused by my own hubris (did some years ago a circuit, I called it Rogeorge Cell, as in Gilbert Cell, but mine

).
However, I never seen such a multiplier, so I thought I might ask if this idea was published or used already.
It is a digitally controlled potentiometer placed between a direct signal and its inverted version, like in the next figure. The input and the signal path is fully analogue, while the multiplication is by a digitally set value. By varying the position of the potentiometer's cursor (the digital set value) a four quadrant multiplication can be made between the analog signal and the digitally set value.
The same idea can be used to build a 4 quadrant multiplier for something other than voltage, if the divider is made out of something different than a digitally controlled potentiometer. I'm thinking here about an optical signal multiplier, or maybe an RF signal.

The block diagram of the multiplier. Here it was drawn as a digitally controlled potentiometer placed between the direct signal and the inverted signal, but the +, the - and the ratio adder can be anything else with the same functionallity.

And this is a prototype with the most left breakout board is for the OpAmps (quadruple OpAmp OPA1654), the next is the digitally controlled potentiometer (double potentiometer, 10k linear, I2C controlled, TLP0202), and the last one is an Arduino nano board (Atmega324) to controll the potentiometer by I2C.
https://hackaday.io/project/7542-rogeorge-cell/Sorry for the shameless plug.
