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

FIELD: radio equipment.

SUBSTANCE: invention relates to the field of radio equipment, as well as measuring equipment, and can be used, e.g., for filtering interference and protecting radio monitoring systems in the short-wave range. A fourth-order band elimination filter containing an input (1) of the apparatus, connected with the signal source (2), an output (3) of the apparatus, connected with the load (4), a second-order input band elimination filter with a first (5) and a second (6) inputs, as well as a main output (7), a first (8) operational amplifier, a first (9) resistor, a second (10) resistor, a second (11) operational amplifier, a third (12) resistor, a first (13) capacitor, a common power source bus (14), a third (15) operational amplifier, a fourth (16), a fifth (17), and a sixth (18) resistor, a fourth (19) operational amplifier, a second (20) capacitor, a seventh (21), an eighth (22), a ninth (23), a tenth (24), an eleventh (25) resistor. The signal source (2) and the load (4) are matched with the common power source bus (14). An output band elimination filter (26) is introduced into the circuit, identical to the input band elimination filter in the composition of the elements, connections between said elements, and functional purpose of the inputs and outputs, containing a first (27) (in.1*) and a second (28) (in.2*) inputs, as well as a main output (29) (out.1*), an additional input adder (30) with a first (31) and a second (32) inputs.

EFFECT: possibility of adjusting the delay band.

2 cl, 6 dwg