Sinusoidal Frequency Doublers Using Operational Amplifiers

This paper proposes a simple sinusoidal frequency-doubling circuit employing operational amplifiers (op amps) with resistors as the only external components. The realization method makes use of the inherent translinear loop at the output stage of the op amp as a means to perform frequency doubling. The response of the circuit is discussed and experimentally demonstrated. © 1988 IEEE