scholarly journals Sequence and spread spectrum time domain reflectometry for transmission line analysis

2007 ◽  
Author(s):  
Jacklyn Reis ◽  
Agostinho L. S. Castro ◽  
João C. W. A. Costa ◽  
Jaume R. I. Riu ◽  
Klas Ericson
Keyword(s):  
Transmission Line ◽  
Time Domain ◽  
Spread Spectrum ◽  
Time Domain Reflectometry ◽  
Line Analysis

scholarly journals Sequence Time Domain Reflectometry for Transmission Line Analysis

2007 ◽  
Author(s):  
Jacklyn Reis ◽  
Agostinho Castro ◽  
João Crisostomo Weyl Albuquerque Costa ◽  
Jaume Riu ◽  
Klas Ericson
Keyword(s):  
Transmission Line ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Line Analysis

Postprocessing for Improved Accuracy and Resolution of Spread Spectrum Time-Domain Reflectometry

2019 ◽  
Vol 3 (6) ◽  
pp. 1-4 ◽  
Author(s):  
Naveen Kumar Tumkur Jayakumar ◽  
Evan Benoit ◽  
Samuel Kingston ◽  
Mashad Uddin Saleh ◽  
Michael Scarpulla ◽  
...  
Keyword(s):  
Time Domain ◽  
Spread Spectrum ◽  
Time Domain Reflectometry ◽  
Improved Accuracy

An Innovative Use of TDR Probes: First Numerical Validations with a Coaxial Cable

2018 ◽  
Vol 23 (4) ◽  
pp. 437-442
Author(s):  
Raffaele Persico ◽  
Iman Farhat ◽  
Lourdes Farrugia ◽  
Sebastiano D'Amico ◽  
Charles Sammut
Keyword(s):  
Magnetic Properties ◽  
Transmission Line ◽  
Time Domain ◽  
Numerical Data ◽  
Time Domain Reflectometry ◽  
Coaxial Cable ◽  
Transmission Line Model ◽  
Properties Of Materials

In this paper we propose a study regarding some possibilities that can be offered by a time domain reflectometry (TDR) probe in retrieving both dielectric and magnetic properties of materials. This technique can be of interest for several applications, among which the characterization of soil in some situations. In particular, here we propose an extension of the paper “Retrieving electric and magnetic propetries of the soil in situ: New possibilities”, presented at the IWAGPR, held in Edinburgh in 2017, and as a new contribution we will validate a transmission line model with numerical data simulated by the CST code.

Distributed Strain Sensing Using Carbon Nanotube Thin Films and Electrical Time-Domain Reflectometry

2018 ◽  
Author(s):  
Bo Mi Lee ◽  
Kenneth J. Loh ◽  
Francesco Lanza di Scalea
Keyword(s):  
Thin Films ◽  
Carbon Nanotube ◽  
Transmission Line ◽  
Time Domain ◽  
Structural Response ◽  
Time Domain Reflectometry ◽  
Distributed Sensing ◽  
Uniaxial Tensile ◽  
Electromagnetic Signal ◽  
Single Measurement

Nondestructive inspection (NDI) is an effective technique to inspect, test, or evaluate the integrity of materials, components, and structures without interrupting the serviceability of a system. Despite recent advances in NDI techniques, most of them are either limited to sensing structural response at their instrumented locations or require multiple sensors and measurements to localize damage. In this study, a new NDI system that could achieve distributed sensing using a single measurement was investigated. Here, piezoresistive carbon nanotube (CNT)-polymer thin film sensors connected in a transmission line setup were interrogated using electrical time-domain reflectometry (ETDR). In ETDR, an electromagnetic signal is sent from one end of the transmission line. When the signal encounters the sensor, it can partially reflect and be captured at the same point. The characteristics of the reflected signal depend on the sensor’s impedance, which is correlated to structural response, deformation, or damage. The advantage of this is that distributed sensing along the entire transmission line can be achieved using a single measurement point. To validate this concept, CNT-polymer thin films that were integrated with a transmission line are subjected to uniaxial tensile strains applied using a load frame. The ETDR signals were analyzed to assess the system’s sensing performance.

Self-sensing time domain reflectometry method for damage monitoring of a CFRP plate using a narrow-strip transmission line

2014 ◽  
Vol 58 ◽  
pp. 59-65 ◽  
Author(s):  
Akira Todoroki ◽  
Hiroumi Kurokawa ◽  
Yoshihiro Mizutani ◽  
Ryosuke Matsuzaki ◽  
Tetsuo Yasuoka
Keyword(s):  
Transmission Line ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Narrow Strip ◽  
Cfrp Plate ◽  
Damage Monitoring ◽  
Sensing Time

Spread Spectrum Time Domain Reflectrometry Applied to Electrical Systems in Nuclear Power Plants

2010 ◽  
Author(s):  
Gary M. Sandquist ◽  
Carl J. Sandquist
Keyword(s):  
Time Domain ◽  
Integrated Circuit ◽  
Spread Spectrum ◽  
Power Plants ◽  
Short Circuit ◽  
Time Domain Reflectometry ◽  
Nuclear Plant ◽  
Current Time ◽  
Electrical Systems ◽  
On Line

A recently developed technique “Spread Spectrum Time Domain Reflectometry” (SSTDR), and supporting test devices will be adapted and tested to monitor and diagnose nuclear plant electrical systems. Current time domain reflectometry methods cannot detect or locate small faults after arc fault events, because their impedance discontinuity is too small and transient to create a measurable reflection. However, on-line, unobtrusive SSTDR can detect and locate arc and other electrical faults when the (∼msec) short circuit returns a strong reflected signal. These observations have led to development of SSTDR. If SSTDR can be successfully adapted to present and future nuclear plant electrical systems, it will be possible to monitor, on-line, the integrity of the electrical system continuously and with only minor equipment modification and no consequential safety issues. An integrated circuit (IC) is under development at the University of Utah for applications in the aircraft industry that will be adapted and used for this proposed development.

scholarly journals Laboratory Evaluation of Railroad Crosslevel Tilt Sensing Using Electrical Time Domain Reflectometry

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4470
Author(s):  
Sijia Li ◽  
Chi-Lin Chen ◽  
Kenneth J. Loh
Keyword(s):  
Transmission Line ◽  
Time Domain ◽  
Pulse Signal ◽  
Time Domain Reflectometry ◽  
Laboratory Evaluation ◽  
Track Geometry ◽  
Railroad Tracks ◽  
Printed Sensors ◽  
The Difference ◽  
Tilt Sensors

Crosslevel is defined as the difference in elevation between the top surface of two railroad tracks. Severe changes in crosslevel, for example, due to earthquakes, ground settlement, or crushed ballasts, affect track geometry and can cause train derailment. Therefore, the objective of this study was to monitoring railroad crosslevel by using electrical time domain reflectometry (ETDR) to simultaneously interrogate multiple capacitive tilt sensor prototypes connected in a transmission line. ETDR works by propagating an electrical pulse signal from one end of the transmission line and then monitoring the characteristics of each reflected pulse, which is affected by the capacitance (or tilt) of the sensors. This study begins with a discussion of the capacitive tilt sensor’s design. These 3D-printed sensors were tested to characterize their tilt sensing performance. Then, multiple tilt sensors were connected in a transmission line and interrogated by ETDR. The ability to use ETDR to multiplex and interrogate sensors subjected to different angles of tilt was validated.

Spread Spectrum Time Domain Reflectometry for Health Monitoring of Solar Arrays

2021 ◽  
Author(s):  
Joel B. Harley ◽  
Ayobami Edun ◽  
Cody Laflamme ◽  
Samuel Kingston ◽  
Evan Benoit ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Time Domain ◽  
Spread Spectrum ◽  
Time Domain Reflectometry ◽  
Solar Arrays

Spread Spectrum Time Domain Reflectometry and Steepest Descent Inversion Spread Spectrum Time Domain Reflectometry and Steepest Descent Inversion

2021 ◽  
Vol 36 (2) ◽  
pp. 190-198
Author(s):  
Samuel Kingston ◽  
Hunter Ellis ◽  
Mashad Saleh ◽  
Evan Benoit ◽  
Ayobami Edun ◽  
...  
Keyword(s):  
Time Domain ◽  
Spread Spectrum ◽  
Complex Impedance ◽  
Time Domain Reflectometry ◽  
Steepest Descent ◽  
Model Parameters ◽  
Inversion Algorithm ◽  
Parametric Function ◽  
Descent Algorithm ◽  
Steepest Descent Algorithm

In this paper, we present a method for estimating complex impedances using reflectometry and a modified steepest descent inversion algorithm. We simulate spread spectrum time domain reflectometry (SSTDR), which can measure complex impedances on energized systems for an experimental setup with resistive and capacitive loads. A parametric function, which includes both a misfit function and stabilizer function, is created. The misfit function is a least squares estimate of how close the model data matches observed data. The stabilizer function prevents the steepest descent algorithm from becoming unstable and diverging. Steepest descent iteratively identifies the model parameters that minimize the parametric function. We validate the algorithm by correctly identifying the model parameters (capacitance and resistance) associated with simulated SSTDR data, with added 3 dB white Gaussian noise. With the stabilizer function, the steepest descent algorithm estimates of the model parameters are bounded within a specified range. The errors for capacitance (220pF to 820pF) and resistance (50 Ω to 270 Ω) are < 10%, corresponding to a complex impedance magnitude |R +1/jωC| of 53 Ω to 510 Ω.

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