BAND-PASS LC FILTER WITH CONSTANT INPUT RESISTANCE IN STOP-BANDS Russian patent published in 2014 - IPC H03H7/09 H03H7/12 

FIELD: radio engineering, communication.

SUBSTANCE: disclosed device relates to radio electronics and can be used as selectors of professional-grade transceivers. The band-pass LC filter with constant input resistance in stop-bands comprises a first inductance coil, the first lead of which is connected to the input potential terminal of the filter, the second lead of the inductance coil is connected to a first capacitor, the second lead of which is connected to second and third capacitors, the second lead of the third capacitor is connected to a second inductance coil, the second lead of which is connected to fourth and fifth capacitors, the second lead of the fifth capacitor is connected to a third inductance coil, the second lead of which is the potential output of the filter, the second leads of the second and fourth capacitors are connected to a common bus; the device also comprises an additional circuit which consists of a fourth inductance coil, the first lead of which is connected to the input potential terminal of the filter, the fourth inductance coil is connected in parallel to a sixth capacitor, the second lead of the fourth inductance coil is connected to a resistor and a fifth inductance coil, the second lead of which is connected to a seventh capacitor, the second leads of the seventh capacitor and the resistor are connected to the common bus.

EFFECT: improved standing wave ratio at the input of the filter in stop-bands.

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