ACTIVE FILTER OF FOURTH-ORDER LOW FREQUENCIES Russian patent published in 2006 - IPC H03H11/12 

FIELD: radio engineering, possible use for realization of filtering equipment with high selectivity coefficients.

SUBSTANCE: in accordance to invention, first amplifier K1 (dwg.1) is connected between RC-bridge of fourth order and input of second amplifier K2. output of first amplifier K1 is connected to second outputs of first-third capacitors C1-C3 of fourth order RC-bridge, while through fifth resistor R5 it is connected to second clamp of fourth capacitor C4 of bridge. Output of second amplifier K2 through fifth capacitor C5 is connected to common point C4 and R5, through sixth capacitor C6 - to common point of first and second resistors R1,R2 and C1 of the bridge. As a result, decreased values of sensitivity of transfer function to deviation of parameters of amplifiers K1, K2 is the cause for increased dynamic and frequency ranges of filter.

EFFECT: increased dynamic and frequency ranges.

5 dwg