Analog multiplier using operational amplifiers

Simple circuit technique for implementing four-quadrant analog multiplier has been presented. The proposed circuit requires only operational amplifier (opamp) as the active element. The realization method is based on the quarter-square technique where a square is provided from the inherent quadratic behaviour of class-AB output stage of opamp. Experimental results showing the circuit performance are described. The wore-case linearity error and total harmonic distortion for maximum operating range are about 0.23 and 1.02%, respectively.