Filter circuit having a resonator operated in series resonance

摘要

A description is given of a filter circuit having a resonator operated in series resonance; this comprises: a) a two-pole resonator circuit having a resonator whose conductance can be divided into a useful component and a parasitic component, b) a compensation circuit having two connections, which circuit reproduces the parasitic component of the resonator conductance, c) a differential stage comprising two active elements which each have a base connection, an input connection and an output connection, the base connection being connected in each case to a connection of the two-pole resonator circuit and the input connection being connected in each case to a connection of a signal source, and the output connections forming the outputs of the differential stage, d) a negative-impedance converter having a first pair of terminals and a second pair of terminals, the connections of the first pair of terminals being connected to one connection each of the compensation circuit and to one current source each and the connections of the second pair of terminals being connected to one base connection each of the active elements of the differential stage, e) an evaluation circuit which is connected to the two output connections of the active elements of the differential stage.