Second order active RC filters with a single operational amplifier

Abstract

The paper deals with economic realizations of second order active RC filters employing a single differential input operational amplifier as the active element. All the basic types of filters are considered and the sensitivities of Q arid undamped natural frequency with respect to various parameters are evaluated. Further, it is shown that one circuit configuration can lead to several types of filter realizations having the same Q simply by short circuiting or open circuiting certain elements, thereby reducing the manufacturing cost.