DEMODULATION METHOD OF FIBER OPTIC CURRENT SENSOR SIGNAL Russian patent published in 2019 - IPC G01R15/22 G01R15/24 G01R19/00 

FIELD: measurement technology.

SUBSTANCE: invention relates to the field of optical methods for measuring physical quantities using phase fiber optic sensors, including fiber-optical interferometers used to measure electromagnetic fields. Method for demodulating a fiber optic current sensor signal includes an auxiliary modulation of the phase difference in a phase fiber optic sensor by a harmonic signal, extracting from the signal received from a photodetector installed at an output of the phase fiber optic sensor, voltages of the first and second harmonics of the auxiliary modulation frequency, synchronous detection of the voltages of the first and second harmonics of the auxiliary modulation frequency, and the calculation of the desired phase difference. In this case, emit the voltage of the fourth harmonic of the auxiliary phase modulation frequency, detect synchronously and calculate the value of the sought voltage phase difference from the outputs of the first, second and fourth harmonic detectors using the proposed formula.

EFFECT: improving the demodulation accuracy of the fiber optic current sensor signal when the amplitude of the auxiliary modulation of the phase difference varies with the phase fiberoptic sensor in the harmonic signal.

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