ACTIVE POLAR PIEZO-ELECTRIC FILTER Russian patent published in 2007 - IPC H03H9/54 

FIELD: radio-electronics, possible use for frequency selection of signals.

SUBSTANCE: in accordance to the invention, active band piezo-electric filter, containing two piezo-resonator, first contacts of which are connected to input clamp of filter, to second contacts of first and second piezo-resonators first contacts of first and second resistors respectively are connected, and algebraic adder (subtracter), made on basis of operational amplifier with resistive negative check connection, output of which is the output of filter, to inverting input of operational amplifier, third resistor is connected, to non-inverting input of operational amplifier, fourth and fifth resistors are connected, second contact of fifth resistor is connected to common bus, introduced additionally are first and second capacitors, while first contact of first capacitor is connected to second contact of first resistor and to second contact of third resistor, while first contact of second capacitor is connected to second contact of second resistor and to second contact of fourth RS, second contacts of first and second capacitors are connected to common bus.

EFFECT: decreased level of noises.

1 dwg