FREQUENCY-SELECTIVE PHOTOCONVERTER OF OPTICAL RADIATION Russian patent published in 2015 - IPC G01J1/44 

FIELD: instrumentation.

SUBSTANCE: device contains photo diode, power source, differential amplifier, field transistor, its gate is connected to plate of the first capacitor, control voltage source, variable-capacitance diode and inductive-capacitance loop. Output of the differential amplifier via the inductive-capacitance loop is connected with gate of the field transistor, its source via the first resistor is connected to the second plate of the first capacitor, and to cathode of the photo diode, that via the second resistor is connected with the inverting input of the differential amplifier, that via the second capacitor is connected to its output. Cathode of the variable-capacitance diode via the third resistor is connected with control voltage source, and via the third capacitor is connected to the gate of the field transistor, its drain is connected with the power source, and its source is output of the device.

EFFECT: assurance of high selective sensitivity within narrow band of frequencies upon presence of large permanent illumination or noise emission.

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