Quantitative detection of multi-frequency disturbance signal by ϕ -OTDR system

Ya-Jun Wang, Bin Liu*, Juan Liu, Jinhui Yuan*, Yanjun Fu, Xing-Dao He, Qiang Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Recently, the combination of pattern recognition technology and distributed fiber sensing systems has become increasingly common, so whether the disturbance signal can be well recovered has become increasingly important. To verify the recovery and linear response of a distributed fiber optic sensing system to multi-frequency disturbance signals, a heterodyne coherent detection system for phase-sensitive optical time-domain reflectometry is developed. The output beat signal is extracted using the digital in-phase/quadrature demodulation algorithm. The signal can be precisely located on a 7 km length range, and the disturbance signal can be restored well through the phase information. Not only the superposition signal composed of the same signal but also that composed of different kinds of signals can be successfully restored. A fast Fourier transform algorithm is used to obtain the frequency information of the superimposed signal. Combined with the use of a finite impulse response filter, the superposed signal is decomposed according to its frequency components, which perfectly restores the two signals before they are superimposed. In addition, their amplitude is highly linear with the driving voltage of the piezoelectric transducer. The system can fully retain the details of each frequency component in the recovery of multi-frequency disturbance signals. More importantly, in field experiments, the disturbance behavior is well recovered, which has broad prospects in the application of perimeter security.
Original languageEnglish
Article number034002
Pages (from-to)1-13
Number of pages13
JournalMeasurement Science and Technology
Volume34
Issue number3
Early online date8 Dec 2022
DOIs
Publication statusE-pub ahead of print - 8 Dec 2022

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