ACTIVE BAND-PASS PIEZOELECTRIC FILTER Russian patent published in 2001 - IPC

FIELD: radio engineering. SUBSTANCE: invention can be used in the capacity of filter of key selection of radio receiving devices. Filter is manufactured with use of two piezoresonators 1, 2 whose first leads are connected to input potential terminal of filter and whose second leads are connected to common bus via resistors 3, 4. Proposed filter incorporates first operational amplifier 1 with negative feedback 5 and second operational amplifier whose output is connected to inverting input of first negative feedback 5 via resistor 9. Inverting inputs of first and second negative feedbacks 5,6 are connected to resistor 8. Inverting input of second negative feedback is connected to common bus via resistor 7. Second leads of first and second piezoresonators 1, 2 are connected to inverting inputs of second and first operational amplifiers with negative feedbacks 6, 5 correspondingly. EFFECT: low level of noise, high level of attenuation in attenuation band. 3 dwg, 1 tbl