Evaluation of the load impedance in coaxial cable via time-frequency domain reflectometry

Shin, Yong June; Powers, E.J.; Choe, Tok Son; Sung, Soo Hak; Yook, Jong Gwan; Park, Jin Bae

doi:10.1117/12.505379

Cited by 5 publications

(7 citation statements)

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“…Also, the accuracy of impedance measurement by TDR is limited within comparatively neighborhood of reference characteristic impedance [2]. TFDR has been suggested to enhance accuracy in detection and localization of the faults in a coaxial cable [3], and as an extension of TFDR applications, a new load impedance evaluation methodology based on TFDR has been suggested in order to resolve the accuracy limitations of measurement range in classical reflectometry [4]. TFDR transmits a reference signal characterized by a chirp signal with Gaussian envelope which enables one to achieve time localization and to assign energy in the frequency band of interest.…”

Section: Introductionmentioning

confidence: 99%

Load Impedance Measurement on a Coaxial Cable via Time-Frequency Domain Reflectometry

Kwak

Yoon

Park³

2006

2006 SICE-ICASE International Joint Conference

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In this paper, a new signal processing based methodology which is able to measure a load impedance with high accuracy and resolution is implemented. This methodology is characterized by a chirp signal with Gaussian envelope which enables one to achieve time localization and to assign energy in the frequency band of interest at the same time.For an evaluating the reflection coefficient and estimating the fault distance on a cable a normalized time-frequency crosscorrelation function is utilized, and a cross time-frequency distribution function is used to acquire the phase difference between the input and the reflected signals. The real impedance measurement experiments have been carried out using a time-frequency domain reflectometry (TFDR) system on a coaxial cable with various sorts of terminal resistors. The experimental results of the TFDR based impedance measurement are compared with those of the commercial time domain reflectometry (TDR). The proposed TFDR based impedance measurement methodology shows that it is able to evaluate the location of fault on a coaxial cable and it can offers information of the fault as the load impedance.

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Section: Introductionmentioning

confidence: 99%

Load Impedance Measurement on a Coaxial Cable via Time-Frequency Domain Reflectometry

Kwak

Yoon

Park³

2006

2006 SICE-ICASE International Joint Conference

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“…However, TDR has some disadvantages. For example, the precise energy ratio between 3 Author to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

“…the reference signal and the reflected signal cannot be obtained [3][4][5] and the method is significantly affected by noise. It also has limitations in terms of the resolution and accuracy of fault detection due to the rise/fall time [6,7].…”

Section: Introductionmentioning

confidence: 99%

Measurement of load impedance in power cables using wavelet-transform-based time–frequency domain reflectometry

Lee¹,

Park²,

Choi³

2013

Meas. Sci. Technol.

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In this paper, wavelet-transform-based time–frequency domain reflectometry (WTFDR) is proposed for load impedance measurement. In order to measure the load impedance, the energy of the measured signal in the time–frequency domain, the phase difference between the reference signal and the reflected signal, the characteristic impedance, and the attenuation factor of the measured cable must all be known. Since the complex wavelet transform is composed of real and imaginary parts, the phase difference is easily obtained using the ratio of the real coefficient to the imaginary coefficient. In addition, the wavelet energy denotes the sum of the square of the modulus of the wavelet transform and describes the energy of the measured signal in the time and frequency domains. To accurately determine the characteristic impedance and attenuation factors, the power cable should be estimated as a coaxial cable. Using WTFDR with the complex mother wavelet and the estimated power cable, the load impedance can be obtained simply and accurately. Finally, real experiments for the evaluation of various load impedances are carried out to confirm the effectiveness and accuracy of the proposed method compared to the conventional time–frequency domain reflectometry.

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“…CONCLUSIONS In this paper, TFDR-based impedance measurement methodology proposed in [2] is implemented. TFDR allows one to compensate the error of impedance measurement caused by distortion in transmission line by measuring phase difference and local frequency offset between the input and the reflected signals.…”

Section: B Calculation Of Phasementioning

confidence: 99%

“…As an extension of TFDR application, a new evaluation methodology of the load impedance based on the TFDR [2] was suggested in order to resolve the accuracy limitations in classical reflectometry. The TFDR systems is characterized by a chirp signal with Gaussian envelope which enables one to achieve time localization and to assign energy in the frequency band of interest, a normalized time-frequency cross correlation function to evaluate the magnitude of reflection coefficient, and a cross time-frequency distribution function to acquire the phase difference between the incident and the reflected signals.…”

Section: Introductionmentioning

confidence: 99%

The Load Impedance Measurement in the Time-Frequency Domain Reflectometry System

Choe

Kwak

Shin³

et al.

2005 IEEE Instrumentationand Measurement Technology Conference Proceedings

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In this paper, a new signal processing based methodology is suggested in order to measure the load impedance with high accuracy and resolution. This methodology is characterized by a chirp signal with Gaussian envelope which enables one to achieve time localization and to assign energy in the frequency band of interest. A normalized time-frequency cross correlation function is utilized to evaluate the reflection coefficient, and a cross time-frequency distribution function is used to acquire the phase difference between the input and the reflected signals. In this paper, the real experiments are achieved on a coaxial cable which is the typical transmission line in the electrical wiring system by using the time-frequency domain reflectometry (TFDR) system and terminal resistors to verify the performance of the suggested methodology. The experimental results of the TFDR based impedance measurement are compared with those of the commercial time domain reflectometry (TDR) system.

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Evaluation of the load impedance in coaxial cable via time-frequency domain reflectometry

Cited by 5 publications

References 0 publications

Load Impedance Measurement on a Coaxial Cable via Time-Frequency Domain Reflectometry

Load Impedance Measurement on a Coaxial Cable via Time-Frequency Domain Reflectometry

Measurement of load impedance in power cables using wavelet-transform-based time–frequency domain reflectometry

The Load Impedance Measurement in the Time-Frequency Domain Reflectometry System

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