NARROW-BAND ACTIVE PIEZOELECTRIC FILTER Russian patent published in 1998 - IPC

FIELD: radio electronics; frequency selection of narrow-band signals. SUBSTANCE: filter has negative-feedback operational amplifier whose output functions as filter output, noninverting input is connected through fifth resistor to common bus, first piezoelectric resonator is connected through first resistor to inverting input of operational amplifier and to first lead of second resistor whose second lead is used as filter input, second piezoelectric resonator is connected to third resistor and through fourth resistor, to inverting input of operational amplifier; second lead of each respective first and second piezoelectric resonator is connected to first lead of first or second reactivity simulator whose second lead is connected to common bus; first and second reactivity simulators are built around feedback operational amplifiers whose inverting inputs function as first leads of respective reactivity simulators whose second leads are capacitor plates; second plate of each capacitor is connected to noninverting input and through temperature-depending two-terminal resistive network, to operational amplifier in each reactivity simulator. EFFECT: improved temperature stability of amplitude-frequency response of filter. 4 cl