Continuous-time active-RC filter model for computer-aided design and optimization

A general circuit model is presented for integrator-based continuous-time active-RC filters, consisting of inverting amplifiers and a passive feedback network. The structure is analyzed using a matrix description and the explicit transfer-function formula is given for the general case. Extensions of the model are given that take into account finite dc gain and bandwidth of operational amplifiers, as well as other nonideal effects. Noise analysis of the active-RC filters is performed in a general setting. The matrix-based approach is formulated especially for the efficient use in computer-aided analysis and design of active-RC filters. As illustrations, a few application examples of the proposed approach are given.