Optimum-sensitivity active RC bandpass filter

A realisation is given for a 2-pole bandpass filter that requires only resistors and capacitors as passive elements and a negative-immittance convertor as an active element. The realisation uses fewer components than other realisations, is optimally insensitive to variations in the gain of the negative-immittance convertor and provides for independent adjustment of both the resonant frequency and the Qfactor of the circuit.