SELECTIVE AMPLIFIER Russian patent published in 2013 - IPC H03F3/00 

FIELD: radio engineering, communication.

SUBSTANCE: selective amplifier has an input signal source, a first input transistor whose collector is connected through a first frequency-setting resistor to a first power supply bus and the emitter is connected through a first current-stabilising two-terminal circuit to a second power supply bus, an output transistor whose collector is connected to the first power supply bus and the emitter is connected through a second current-stabilising two-terminal circuit to the second power supply bus, a first balancing capacitor connected between the emitter of the output transistor and the emitter of the input transistor. The input signal source is connected to the collector of the input transistor and the base of the output transistor through a second balancing capacitor; the base of the input transistor is connected through alternating current to the common power supply bus and the output of the device is connected to the emitter of the input transistor through the first balancing capacitor.

EFFECT: high Q-factor of the amplitude-frequency curve of the selective amplifier and its voltage gain at quasi-resonance frequency f₀.

3 cl, 7 dwg