PIEZOELECTRIC FILTER Russian patent published in 2003 - IPC

FIELD: radio electronics; frequency selection of signals. SUBSTANCE: filter has piezoelectric resonators 1- 4, series-connected capacitors 6-10, inductance coils 5, 11; additional capacitors 12-14 and capacitor 6 are parallel-connected between common bus and point of connection of capacitor 12 and piezoelectric resonator 1; inductance coil 11 and capacitor 10 are parallel-connected between common bus and point of connection of piezoelectric resonator 4 and capacitor 13. Capacitors 7, 8, 9 are connected between common bus and respective leads of piezoelectric resonators 2, 3. Capacitor 14 is connected between first lead of piezoelectric resonator 2 and second lead of piezoelectric resonator 3. In addition series-connected inductance coil 15, capacitor 16 and inductance coil 17, capacitor 18 are inserted between common bus and capacitor 14. EFFECT: improved filter selectivity. 2 cl, 3 dwg