Two-amplifier active-RC biquads with minimized dependence on op-amp parameters

It is generally recognized that the best two-amplifier active-
RC
biquads show a better performance with lower sensitivities than single-amplifier biquads (SAB's), and that the performance of an SAB can be improved by use of a composite amplifier. In this paper it is demonstrated that by matching the characteristics of a composite amplifier to the specific filter's requirements a "composite single-amplifier biquad" (CAB) can be obtained with significantly better performance than that of the best two-amplifier biquads reported to date. The resulting circuits are shown by theory and experiment to belong to the best available active-
RC
filters.