TUNABLE LC BAND-PASS FILTER Russian patent published in 2012 - IPC H03H7/00 

FIELD: radio engineering.

SUBSTANCE: tunable LC band-pass filter, consisting of an input band-pass filter, having a first inductance coil whose first lead is connected to the input potential terminal of the filter and the second lead is connected to a first capacitor and a second inductance coil, the second leads of the second inductance coil and the first capacitor are connected to a common bus, and an output band-pass filter, having a third inductance coil whose first lead is connected to the output potential terminal of the filter and the second lead is connected to a second capacitor and a fourth inductance coil, the second leads of the second capacitor and the fourth inductance coil are connected to the common bus; the device further includes a first signal bus which is connected to the second lead of the first inductance coil and a second signal bus which is connected to the second lead of the third inductance coil; the device also includes N structure-identical sections, each having a third, a fourth and a fifth capacitor, as well as an input and an output electronic switch, wherein the third capacitor is connected by the first lead to the first lead of the fourth capacitor and simultaneously to the first lead of the input electronic switch, the second lead of which is connected to the first signal bus; the second lead of the fourth capacitor is connected to the first lead of the fifth capacitor and simultaneously to the first lead of the output electronic switch, the second lead of which is connected to the second signal bus, wherein the second leads of the third and fifth capacitors are connected to the common bus.

EFFECT: high transfer constant of the tunable band-pass circuit at operating frequency.

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