SELECTIVE AMPLIFIER Russian patent published in 2013 - IPC H03F3/45 

FIELD: radio engineering, communications.

SUBSTANCE: in a selective amplifier a collector of an output transistor (3) is connected by AC with a common bus of sources of supply (11) via serially connected the first (9) and additional (12) frequency-setting capacitors, the common unit of which is connected with an output of a device (13) and via the second (8) frequency-setting resistor is connected with a current-stabilising dipole (6), an emitter of the output transistor (3) is connected with the current-stabilising dipole (6) via an additional forward-biased p-n transition (14), the collector of the output transistor (3) is connected with the second (10) bus of the source of supply via the first (7) frequency-setting resistor, in parallel to the additional forward-biased p-n transition (14) there is an emitter-base transition of an auxiliary transistor (15), the collector of which is connected with the first (5) bus of the source of supply.

EFFECT: reduction of total power consumption and as a result of higher quality of selective amplifier amplitude-frequency characteristic and its amplification ratio by voltage at quasiresonance frequency f₀.

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