Analog multiplier using quadritail circuits

Abstract From the Canadian patent

A multiplier containing first and second quadritail cells. The first quadritail cell has a first pair of first and second transistors, a second pair of third and fourth transistors and, a first constant current source for driving the first and second pairs. The second quadritail cell has a third pair of fifth and sixth transistors, a fourth pair of seventh and eighth transistors, and a second constant current source for driving the third and fourth pairs. Each of the first to fourth pairs has output ends coupled together. A first input voltage is applied between input ends of the first and fourth transistors and is applied between input ends of the fifth and eighth transistors. A second …