An Eight-Octant bipolar junction transistor analog multiplier circuit and its applications

This paper presents a circuit topology for an eight-octant analog multiplier implemented using bipolar junction transistors. The proposed circuit is an extension of four-quadrant Gilbert multiplier. The possibility of multiplying three input signals using the proposed circuit is theoretically proved. A scheme to upgrade this circuit to operate for large input signals is also proposed. Theoretical results are validated through spice simulations for small input signals. The possible use of the proposed circuit as a three input mixer, three input emitter coupled logic, or two input multiplier with an enable/disable switch is shown through spice simulations.