Low-frequency differentiators and integrators for biomedical and seismic signals

A general active-network synthesis approach to inverse system design is introduced. The approach is applied to a passive RC differentiator and a passive RC integrator to obtain, respectively, a very low-frequency differential integrator and a very low-frequency differential differentiator. The frequency ranges of the proposed circuits, from dc to a few hundred hertz, are particularly suitable to the frequency ranges of biomedical and seismic signals. The advantages of the proposed circuits are delineated and include single time constants, dc stable integrators, and resistive input differentiators. Noninverting and inverting differentiators and integrators could be obtained by grounding one of the input terminals in the differential configurations.