An Active Biquadratic Building Block Without External Capacitors

A new configuration requiring no external capacitors in the realization of the biquadratic voltage transfer function is developed. The proposed network contains resistors and two operational amplifiers represented by the one-pole roll-off model. It has very low sensitivities with respect to all passive and active parameters, and is suitable for medium- high-frequency applications. Laboratory experiments confirm the validity of the theory and demonstrate the versatility of the circuit as the biquadratic building block.