• Title, Summary, Keyword: Time domain reflectometry

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Estimation of Fault Location on a Transmission Line via Time-Frequency Domain Reflectometry (시간-주파수 반사파 계측 방법을 이용한 전송선로의 결함 위치 추정)

  • Choe TokSon;Kwak Ki-Seok;Yoon Tae Sung;Park Jin Bae
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.9
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    • pp.521-530
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    • 2005
  • In this paper, a new high resolution reflectometry scheme, time-frequency domain reflectometry(TFDR), isproposed to detect and estimate a fault in a transmission line. Traditional reflectometry methodologies have been achieved either in the time domain or in the frequency domain only. However, the TFDR can jump over the performance limits of the traditional reflectometry methodologies because the acquired signal is analyzed in time and frequency domain simultaneously. In the TFDR, the new reference signal and the novel TFDR algorithm are proposed for analyzing the acquired signal in the time-frequency domain. Because the reference signal of Gaussian envelop chirp signal is localized in the time and frequency domain simultaneously, it is suitable to the analysis in the time-frequency domain. In the proposed TFDR algorithm, the time-frequency distribution function and the normalized time-frequency cross correlation function are used to detect and estimate a fault in a transmission line. That algorithm is verified for real-world coaxial cables which are typical transmission line with different types of faults by the TFDR system composed of real instruments. The performance of the TFDR methodology is compared with that o( the commercial time domain reflectomeoy(TDR) experiments, so that concludes the TFDR methodology can detect and estimate the fault with smaller error than TDR methodology.

Detection and Estimation of a Faults on Coaxial Cable with TFDR Algorithm (Time Frequency Domain Reflectometry 기법을 이용한 Coaxial Cable에서의 결함 감지 및 추정)

  • Song, Eun-Seok;Shin, Yong-June;Choe, Tok-Son;Yook, Jong-Gwan;Park, Jin-Bae;Powers, Edward J.
    • The Journal of Advanced Navigation Technology
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    • v.7 no.1
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    • pp.38-50
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    • 2003
  • In this paper, a new high resolution reflectometry scheme, time-frequency domain reflectometry (TFDR), is proposed to detect and locate fault in wiring. Traditional reflectometry methods have been achieved in either the time domain or frequency domain only. However, time-frequency domain reflectometry utilizes time and frequency information of a transient signal to detect and locate the fault. The time-frequency domain reflectometry approach described in this paper is characterized by time-frequency reference signal design and post-processing of the reference and reflected signals to detect and locate the fault. Design of the reference signal in time-frequency domain reflectometry is based on the determination of the frequency bandwidth of the physical properties of cable under test. The detection and estimation of the fault on the time-frequency domain reflectometry relies on the time-frequency domain reflectometry is compared with commercial time domain reflectomtery (TDR) instrument. In these experiments provided in this paper, TFDR locates the fault with smaller error than TDR. Knowledge of time and frequency localized information for the reference and reflected signal gained via time-frequency analysis, allows one to detect the fault and estimate the location accurately.

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A critical comparison of reflectometry methods for location of wiring faults

  • Furse, Cynthia;Chung, You Chung;Lo, Chet;Pendayala, Praveen
    • Smart Structures and Systems
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    • v.2 no.1
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    • pp.25-46
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    • 2006
  • Aging wiring in buildings, aircraft and transportation systems, consumer products, industrial machinery, etc. is among the most significant potential causes of catastrophic failure and maintenance cost in these structures. Smart wire health monitoring can therefore have a substantial impact on the overall health monitoring of the system. Reflectometry is commonly used for locating faults on wire and cables. This paper compares Time domain reflectometry (TDR), frequency domain reflectometry (FDR), mixed signal reflectometry (MSR), sequence time domain reflectometry (STDR), spread spectrum time domain reflectometry (SSTDR) and capacitance sensors in terms of their accuracy, convenience, cost, size, and ease of use. Advantages and limitations of each method are outlined and evaluated for several types of aircraft cables. The results in this paper can be extrapolated to other types of wire and cable systems.

The Comparative Effect of Time-Frequency Distribution Function in a Time-Frequency Domain Reflectometry System (시간-주파수 영역 반사파 계측 시스템에서 다양한 시간-주파수 분포 함수의 영향 연구)

  • Kwak, Ki-Seok;Tok, Son-Choe;Tae, Sung-Yoon;Jin, Bae-Park;Jae, Won-Kho
    • Proceedings of the KIEE Conference
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    • pp.2149-2151
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    • 2004
  • The time-frequency domain reflectometry(TFDR) is well known to detect and locate a fault in a coaxial cable[3]. Traditional reflectometry methods have been achieved in either the time domain or frequency domain only. However, the time-frequency domain reflectometry utilizes time and frequency information of a reflected signal passed through a cable to detect and locate the fault. The purpose of this paper is to find appropriate time-frequency distribution function suitable for a TFDR system. Choosing the appropriate time-frequency distribution function implies one can detect the fault and estimate the location accurately. We consider and compare adequate time-frequency distribution function on the basis of experimental results.

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Frequency Estimation for Time-Frequency Domain Reflectometry using Weighted Robust Least Squares Filter (시간-주파수 영역 반사파 시스템에서 가중강인최소자승 필터를 이용한 주파수 추정)

  • Kwak, Ki-Seok;Ra, Won-Sang;Doo, Seung-Ho;Choi, G.H.;Yoon, Tae-Sung;Park, Jin-Bae;Koh, Jae-Won
    • Proceedings of the KIEE Conference
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    • pp.1640-1641
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    • 2007
  • In this paper, an experiment of weighted robust least squares frequency estimation for the Gaussian envelope chirp signal which is used in the time-frequency domain reflectometry system was carried out. By incorporating the forgetting factor to the frequency estimator, the weighted robust least squares filter achieved good enough frequency estimation performance for the chirp signal and it can be adopted to implement not only low cost time-frequency domain reflectometry but also real-time time-frequency domain reflectometry implementation.

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Performance Comparison and Improvement of STDR/SSTDR Schemes Using Various Sequences (여러 가지 수열을 적용한 STDR/SSTDR 기법의 성능 비교 및 개선)

  • Han, Jeong Jae;Park, So Ryoung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.11
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    • pp.637-644
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    • 2014
  • This paper investigates the detection performance of fault location using STDR(sequence time domain reflectometry) and SSTDR(spread spectrum time domain reflectometry) with various length and types of sequences, and then, proposes an improved detection technique by eliminating the injected signal in SSTDR. The detection error rates are compared and analyzed in power line channel model with various fault locations, fault types, and spreading sequences such as m-sequence, binary Barker sequence, and 4-phase Frank sequence. It is shown that the proposed technique is able to improve the detection performance obviously when the reflected signal is weak or the fault location is extremely close.

Detection Performance Improvement of STDR/SSTDR Schemes Using Sign Eliminator (부호 제거기를 활용한 STDR/SSTDR 기법의 탐지 성능 개선)

  • Park, So Ryoung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.6
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    • pp.620-627
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    • 2016
  • This paper proposes an advanced detection technique for cable fault by eliminating the sign of reference signal in STDR(sequence time-domain reflectometry) and SSTDR(spread-spectrum time-domain reflectometry). The proposed fault-detection technique can eliminate the reference signal more effectively than the conventional one since the sign detector can approximately recover the distorted reference signal by cable and connector, and consequently, can detect the reflected signal by fault more effectively than the conventional one. Especially, it is shown that the error rate of proposed technique can be significantly lower than the conventional one in the case of far fault simulation.

Detection and Estimation of Multiple Faults on a Coaxial Cable Based on TFDR Algorithm (TFDR 기법을 이용한 Coaxial Cable상에 존재하는 다양한 결함 감지 및 추정)

  • 송은석;신용준;육종관;박진배
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.10
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    • pp.1079-1088
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    • 2003
  • In this paper, we propose a high-resolution time-frequency domain reflectometry technique as a methodology of detection and estimation of faults on a wire. This method adopts the time-frequency cross correlation characteristics of the observed signal in both time and frequency domains simultaneously. The accuracy of the proposed method is verified with experiments using a RG type coaxial cable and comparing it with traditional time domain as well as frequency domain reflectometry methods. It is clearly shown here that the proposed algorithm produces excellent results compared to the conventional methods for single as well as multiple fault cables.

Implementation of TFDR system with PXI type instruments for detection and estimation of the fault on the coaxial cable (동축 케이블의 결함 측정에 있어서 PXI 타입의 계측기를 이용한 개선된 TFDR 시스템의 구현)

  • Choe, Deok-Seon;Park, Jin-Bae;Yun, Tae-Seong
    • Proceedings of the KIEE Conference
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    • pp.91-94
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    • 2003
  • In this paper, we achieve implementation of a Time-Frequency Domain Reflectometry(TFDR) system through comparatively low performance(100MS/s) PCI extensions for Instrumentation(PXI). The TFDR is the general methodology of Time Domain Reflectometry(TDR) and Frequency Domain Reflectometry(FDR). This methodology is robust in Gaussian noises, because the fixed frequency bandwidth is used. Moreover, the methodology can get more information of the fault by using the normalized time-frequency cross correlation function. The Arbitrary Waveform Generator(AWG) module generates the input signal, and the digital oscilloscope module acquires the input and reflected signals, while PXI controller module performs the control of the total PXI modules and execution of the main algorithm. The maximum range of measurement and the blind spot are calculated according ta variations of time duration and frequency bandwidth. On the basis of above calculations, the algorithm and the design of input signals used in the TFDR system are verified by real experiments. The correlation function is added to the TDR methodology for reduction of the blind spot in the TFDR system.

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Estimation Method of Cable Fault Location in Rocket Motors Using M-sequence Signals (M시퀀스 신호를 이용한 로켓 추진기관 케이블 결함 위치 추정 기법)

  • Son, Ji-Hong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.5
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    • pp.84-92
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    • 2020
  • This paper describes the estimation method of cable fault location in rocket motors using M-sequence (Maximal Length Sequence). In order to estimate the location of a cable fault, three methods have been usually used: TDR (Time Domain Reflectometry), FDR (Frequency Domain Reflectometry), and TFDR (Time-Frequency Domain Reflectometry). However, these methods suffer the disadvantage of requiring users to be close to a test field, which is dangerous. The estimation method of cable fault location using M-sequence is proposed to solve this problem. The proposed method can make use of DAS (Data Acquisition System). The experiments were three cases: damaged, open, and short. The RG-58 coaxial cable was used in the experiments. As a result, the proposed method has better performance than that of conventional methods such as TDR and TFDR.