• Title/Summary/Keyword: hydrophone sensor

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A study on the multi-point signal detection, using Passive band-pass filter in FBG Hydrophone (FBG(Fiber Bragg Grating) Hydrophone에서 Passive Band-Pass Filter를 사용한 다중점 신호 검출에 관한 연구)

  • Kim, Kyung-Bok;Kwack, Kea-Dal
    • Journal of Sensor Science and Technology
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    • v.9 no.4
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    • pp.307-315
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    • 2000
  • To set up the arrays system of FBG(Fiber Bragg Grating) Hydrophone sensor and realize the multi-point signal detection for the wide scope underwater, using WDM(Wavelength Division Multiplexing) method and Passive band-pass filter system, underwater acoustic signal detection of the newly designed two FBG Transducers is successfully experimented. As a result of the experiment, it was possible each signal with different frequent signals is detected for the multi-point up to 1.3KHz in underwater. We can, therefore, prove the possibility on the system design of Hydrophone sensor arrays, using the newly made FBG Transducers.

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A Study on The low-frequency Hydrophone Using Single-mode FBG in the Hopper Type WDM be in the Making (단일모드 FBG(Fiber Bragg Grating)을 이용한 Hopper type WDM 개발과 저주파수 수중음향 센서연구)

  • Kim, Kyung Bok
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.12
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    • pp.287-291
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    • 2013
  • The low- frequency hydrophone sensor, using the recently developed FBG has an excellent merits which the existing fiber-optic sensor has and also it has an excellent signal sensing effect in the environment of low-frequency(30Hz-300Hz), not to be detected by the PZT sensor. we have the detection of frequency 19KHz right signals when was using more Hopper lenz WDM than $1{\times}3$ optical coupler. furthermore, we can expect the uitilization of low-frequency signal detection to be used for the military purpose and also it can be developed as the high-sensibility multiplexing through the sensor array system.

A Design and manufacture of acoustic-optic converter in the Uniform FBG hydrophone sensor. (균일한 FBG(Fiber Bragg Grating) Hydrophone의 음향-광변환기 설계 및 제작)

  • Kim, Kyung-Bok;Kwack, Kae-Dal
    • Journal of Sensor Science and Technology
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    • v.9 no.4
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    • pp.281-287
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    • 2000
  • For the improvement of frequency characteristics of FBG(Fiber Bragg Grating) hydrophone sensor, we can detected the frequency ranging to 1.4KHz and acoustic directivity by the development of newly designed diaphragm and united type of FBG.

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Sensitivity Analysis of Fiber Optic Hydrophone for Hollow Cylindrical Mandrel (중공 원통형 광섬유 하이드로폰의 감도 해석)

  • 김정석;윤형규;설재수;남성현
    • Journal of KSNVE
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    • v.9 no.3
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    • pp.565-569
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    • 1999
  • Recently, fiber optic hydrophone is a subject which has attracted as a underwater acoustic sensor. In this study, Finite element modeling of fiber optic hydrophone for hollow cylindrical mandrel was performed and the acoustic sensitivity was calculated to estimate the performance of single element fiber optic hydrophone. And acoustic sensitivity was measured in acoustic water tank to verify the result of simulation. The result of FE analysis and experiment is -126 dB re rad/$\mu$ Pa and -128 dB re rad/$\mu$ Pa respectively.

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A Study on The Multi-point Signal and It's Directivity detection of FBG Hydrophone Using Hopper WDM be in The Making (Hopper WDM을 이용한 FBG(Fiber Bragg Grating) 하이드로폰(Hydrophone)의 다중점신호검출 및 지향성 연구)

  • Kim, Kyung Bok
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.11
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    • pp.156-163
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    • 2015
  • In the using of FBG(Fiber Bragg Grating) developed in home land, we designed and manufactured united FBG acoustic transducers the first in Korea. they are being applied to multi-point signal detection of FBG Hydrophone used Hopper WDM(national patent NO 10-1502954) in the underwater. On united FBG transducers manufactured, we made an demonstrated on respective frequency response peculiarities in the underwater and analyzed the special characters. As the experimental result on frequency response peculiarities, we made it possible underwater acoustic detection on united FBG acoustic transducers type to maximum 30Hz~2.5KHz. it's the optimum conditions of 1.2KHz frequency in detection. And for the purpose of realization on multi-point signal detection on wide scope in the underwater, in the using of WDM(Wavelength Division Multiplexing) method and passive band-pass filter system, established arrays system and succeeded in multi-point underwater acoustic signal detection to the frequency 200Hz~1.3KHz out of the two united type FBG transducers. Additionally, it would be possible directivity detection for the object of its source as the intensity of detection signal varies with the sound source's direction and angle. From now on we prepared a new moment on the practical use study on FBG hydrophone in the future.

Characteristics of Underwater Sound Detection of the Fiber Optic Hydrophone Array (광섬유 하이드로폰 배열의 수중음향 감지특성 연구)

  • Lee, Jong-Kil
    • Journal of Sensor Science and Technology
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    • v.8 no.2
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    • pp.102-107
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    • 1999
  • In this paper, to develop the fiber optic hydrophone for the use of low frequency applications, two channels TDM(Time Division Multiplexing) fiber-optic hydrophone array was fabricated and their acoustic charateristics were investigated in the acoustic water tank. A fiber length of the order of 150m is wounded at the hollow cylinder type aluminum mandrel and the fundamental natural frequency of the mandrel maintained above 10kHz. An unbalanced interferometer (discrete Mach-Zehnder type) was used. Sound detection performance is tested in the underwater tank with 3kHz continuous sound source. Finally, it is shown that two channels TDM fiber-optic hydrophone array can detect 3kHz sound stably. This results can also applicable for the development of multi-channel fiber optic hydrophone array.

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Evaluation of Field Application and Estimation of Bedload Discharge in the Forest Watershed using the Hydrophone (하이드로폰을 이용한 산림유역 소류사 유출량 산정 및 현장 적용성 검토)

  • Seo, Jun-Pyo;Kim, Ki-Dae;Woo, Choong-Shik;Lee, Chang-Woo;Lee, Heon-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.12
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    • pp.807-818
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    • 2020
  • In this study, hydrophones using acoustic sensors were used to estimate the amount of bedload discharge in a forested watershed. The reaction characteristics were analyzed through hydrophone flume tests and field tests, and the quantitative bedload discharge was calculated and compared with that measured by a pit sampler. The hydrophone reaction changed the pulse according to the flow rate change, but did not react to standard sand. The pulse was different depending on the particle size and weight, and accordingly, there was a specific channel showing a suitable response. For a hydrophone installed in the field, by using an automatic impact device, the reaction characteristics of each channel were analyzed to confirm normal operation of the sensor and the suitability of the output value of each channel. In addition, a suitable channel was selected for the estimation of bedload discharge. The bedload discharge formula was developed using a hydrophone pulse and the average flow rate, and was compared with the measured data in the pit sampler in the study site. As a result of the study, if a hydrophone is used for monitoring the bedload in forested watersheds, it is considered effective in quantitatively estimating the weight of bedload discharge.

Experimental Investigation of the Acoustic Signal Detection Performance for an Interfermetric Fiber Optic Hydrophone (실험을 통한 간섭계형 광섬유 청음기의 음향신호 감지성능 연구)

  • 이종길;윤형규;설재수;남성현
    • Journal of KSNVE
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    • v.7 no.6
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    • pp.931-936
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    • 1997
  • Optical fiber sensor is a subject which has been attracted considerable attention in recent years. Detection of sound pressure with optical fibers positioned in the arms of a Mach-Zehnder interferometer is presented in this paper. A fiber length of the order of 150m is wounded is made by hollow cylinder type. To increase the sound signal 3${\times}3$ directional coupler is used. Fiber optic hydrophone is the underwater tank with 2kHz sound source. Finally, it is shown that the fiber optic hydeophone can stably detec 2kHz sound.

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PZT5 spherical hydrophone simulation using a coupled FE-BE method (결합형 유한요소-경계요소 기법을 활용한 PZT5 구형 수중 수파기 시뮬레이션)

  • Jarng, Soon-Suck
    • Journal of Sensor Science and Technology
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    • v.7 no.6
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    • pp.377-385
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    • 1998
  • This paper describes the application of a coupled finite element-boundary element method to obtain the steady-state response of a hydrophone. The particular structure considered is a flooded piezoelectric spherical shell. The hydrophone is three-dimensionally simulated to transduce an incident plane acoustic pressure onto the outer surface of the sonar spherical shell to electrical potentials on inner and outer surfaces of the shell. The acoustic field formed from the scattered sound pressure is also simulated. And the displacement of the shell caused by the externally incident acoustic pressure is shown in temporal motion. The coupled FE-BE method is described in detail.

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Sensitivity Analysis of Fiber Optic Hydrophone for an End-Capped Hollow Cylinder (끝단이 막힌 중공 원통형 광섬유 하이드로폰의 감도 해석)

  • 이종길;윤형규;서인창
    • Journal of KSNVE
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    • v.6 no.4
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    • pp.475-479
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    • 1996
  • Recently, fiber optic hydrophone is a subject which has attracted as a underwater acoustic sensor. In this paper, a length of optical fiber is bonded to an end-capped hollow cylinder of some elastic material, e. g. aluminum and glass-pyres. The normalized sensitivity is derived according to the direction of polarization. Derived sensitivity equations are simulated for two different mandrel materials. The results are also compared to the McMahon's results which calculated for an average Pockel coefficient. Based on the numerical simulation normalized sensitivity is propotional to the inner to outer diameter ratio.

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