FOURTH-ORDER NOTCH FILTER Russian patent published in 2021 - IPC H03H11/12 

FIELD: radio engineering.

SUBSTANCE: invention relates to the field of radio engineering, in particular, for filtering interference and protecting radio-monitoring systems in the short-wave range. The filter contains input (1) of the device connected to signal source (2), output (3) of the device connected to load (4), the second-order input notch filter with first (5) and second (6) inputs, as well as first (7) and second (8) outputs, first (10), second (11) resistors, second operational amplifier (12), third resistor (13), common bus of the power source (14), first capacitor (15), third operational amplifier (16), fourth (17) and fifth (18) resistors, the common node of which is connected to the common bus of power supply (14) through sixth resistor (19), fourth operational amplifier (20), second capacitor (21), seventh resistor (22), eighth resistor (23), ninth resistor (24), tenth resistor (25), eleventh resistor (26), output notch filter (27), identical to the input notch filter in terms of the composition of the elements, the connections between them and the functional purpose of the inputs and outputs, additional input adder (32).

EFFECT: possibility of adjusting the delay band in the fourth-order notch filter.

3 cl, 6 dwg