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

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering and communication and can be used as an interface for limiting the spectrum of the signal source, e.g., in processing thereof with analogue-to-digital converters. An output bandpass filter (26) identical to the input bandpass filter in terms of the composition of elements, the connections between said elements, and the functional purpose of inputs and outputs, containing a first (27) (in.1*) and second (28) (in.2*) inputs, as well as a main output (29) (out.1*), an additional input adder (30), wherein the main output (7) of the second-order input bandpass filter is connected to the second (28) (in.2*) input of the second-order output bandpass filter (26), the main output (29) (out.1*) of the second-order output bandpass filter (26) is connected with the output (3) of the apparatus and the first (31) input of the additional input adder (30), the input (1) of the apparatus is connected to the second (32) input of the additional input adder (30), the output of the additional input adder (30) is connected with the second (6) input of the second-order input bandpass filter, the first (5) input of the second-order input bandpass filter and the first (27) (in.1*) input of the second-order output bandpass filter (26) are matched with the common bus of the power sources (14).

EFFECT: provided possibility of changing the bandwidth and extended frequency range in a fourth-order bandpass filter.

2 cl, 6 dwg