Symmetrical integrator and application of said integrator to an electric filter

摘要

The symmetrical integrator comprises an operational amplifier having two floating inputs and two floating outputs each having a feedback connection to an input via a capacitor. An input capacitor is connected via two MOS transistors to two differential inputs of the integrator or via two additional MOS transistors to the inputs of the operational amplifier. The transfer function of the circuit is a pure integral or a sum of integrals if several input signals are applied to similar pairs of inputs. The integrator permits realization of filters whose transfer function has transmission zeros by utilizing additional inputs together with a direct capacitive coupling.