• Title, Summary, Keyword: 기가헤르쯔 측정기술

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Decision of Optimum Turn Step Resolution for Extraction of the Spurious Radiation in Gigahertz Band (기가헤르쯔 대역 불요파 방사의 최대값 추출을 위한 최적 회전 스텝 분해능 결정)

  • 허민호;윤영중;정삼영;공성식
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.1
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    • pp.8-13
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    • 2003
  • In this paper, suitablility of 1 GHz CISPR limits establishment fur broadcast communication quality protection is examined and the optimum turn step resolution of EUT for spurious measurement of frequency above 1 GHz to increase the accuracy of maximum values extraction is examined. As a result of 500 MHz and 1.7 GHz clock speed personal computer of micro-processor measurement, optimum turn step resolution extracted by National Institution of National Instrument of Standard & Technology(NIST) Koepke method is estimated 40 table positions per polarization in 500 MHz. And in case of 1.7 GHz, step size is 36 table positions. Prediction of turn step size required for fully scan method in gjgahertz measurement will increase measurement accuracy and reduce considerable measurement time as well.

Simultaneous Measurement of Strain and Damage Signal of Composite Structures Using a Fiber Bragg Grating Sensor (광섬유 브래그 격자 센서를 이용한 복합재 구조물의 변형률 및 파손신호 동시 측정)

  • Koh Jong-In;Bang Hyung-Joon;Kim Chun-Gon;Hong Chang-Sun
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.95-102
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    • 2004
  • For the simultaneous measurement of strain and damage signal, a fiber Bragg grating sensor system with a dual demodulator was proposed. One demodulator using a tunable Fabry-Perot filter can measure low-frequency signal such as strain and the other demodulator using a passive Mach-Zehnder interferometer can detect high-frequency signal such as damage signal or impact signal. Using a proposed fiber Bragg grating sensor system, both the strain and damage signal of a cross-ply laminated composite beam under tensile loading were simultaneously measured. Analysis of the strain and damage signals detected by single fiber Bragg grating sensor showed that sudden strain shifts were induced due to transverse crack propagation in the 90 degree layer of composite beam and vibration with a maximum frequency of several hundreds of kilohertz was generated.

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Failure detection of composite structures using a fiber Bragg grating sensor (광섬유 브래그 격자 센서를 이용한 복합재 구조물의 파손 검출)

  • 고종인;김천곤;홍창선
    • Composites Research
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    • v.17 no.2
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    • pp.28-33
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    • 2004
  • Failure detection in a cross-ply laminated composite beam under tensile loading were performed using a fiber Bragg grating (FBG) sensor. A Passive Mach-Zehnder interferometric demodulator was proposed to enhance sensitivity and bandwidth. The proposed FBG sensor system without active device such as a phase modulator is very simple in configuration, easy to implement and enables the measurement of high-frequency vibration with low strain amplitude such as impact or failure signal. Failure signals detected by a FBG sensor had offset value corresponding to the strain shift with vibration at a maximum frequency of several hundreds of kilohertz. at the instant of transverse crack propagation in the 90 degree layer of composite beam.