scholarly journals Determination of structural parameter variations in single-mode optical fibres by time-domain reflectometry

1982 ◽  
Vol 18 (12) ◽  
pp. 489 ◽  
Author(s):  
M.P. Gold ◽  
A.H. Hartog
Keyword(s):  
Time Domain ◽  
Single Mode ◽  
Time Domain Reflectometry ◽  
Structural Parameter ◽  
Optical Fibres ◽  
Parameter Variations

Quantitative, zerstörungsfreie Feuchtemessung in Baustoffen vor Ort mit der Time Domain Reflectometry / Quantitative, non-destructive moisture measurement in building materials on site by time-domain re ectometry

1999 ◽  
Vol 5 (6) ◽  
pp. 609-618
Author(s):  
M. Stacheder ◽  
G. Grassegger ◽  
F. Grüner
Keyword(s):  
Time Domain ◽  
Building Materials ◽  
Salt Content ◽  
Time Domain Reflectometry ◽  
New Method ◽  
Measuring Methods ◽  
Surface Moisture ◽  
Non Destructive ◽  
Floor Cover

Abstract A new commercially available dielectric technique for the non-destructive determination of moisture in building materials based on the principle of 'time-domain reflectometry' (TDR) is presented. TDR measurements on samples of sandstone, brick, concrete and floor cover matched very well with results of conventional moisture measuring methods such as oven-drying or calciumcarbide-technique. The new method showed only a low influence of salt content or surface moisture of the material on the results.

Separation and Determination of the Disturbing Signals in Phase-Sensitive Optical Time Domain Reflectometry (Φ-OTDR)

2015 ◽  
Vol 33 (15) ◽  
pp. 3156-3162 ◽  
Author(s):  
Huijuan Wu ◽  
Shunkun Xiao ◽  
Xiaoyu Li ◽  
Zinan Wang ◽  
Jiwei Xu ◽  
...  
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Optical Time Domain Reflectometry ◽  
Phase Sensitive ◽  
Optical Time

scholarly journals Time domain reflectrometry measurements using a movable obstacle for the determination of dielectric profiles

2008 ◽  
Vol 6 ◽  
pp. 1-4
Author(s):  
B. Will ◽  
M. Gerding ◽  
S. Schultz ◽  
B. Schiek
Keyword(s):  
Dielectric Constant ◽  
Water Content ◽  
Time Domain ◽  
Measurement Techniques ◽  
Measurement Data ◽  
Time Domain Reflectometry ◽  
Dielectric Measurement ◽  
Effective Dielectric Constant ◽  
Pulse Delay

Abstract. Microwave techniques for the measurement of the permittivity of soils including the water content of soils and other materials, especially TDR (time domain reflectometry), have become accepted as routine measurement techniques. This summary deals with an advanced use of the TDR principle for the determination of the water content of soil along a probe. The basis of the advanced TDR technique is a waveguide, which is inserted into the soil for obtaining measurements of the effective soil permittivity, from which the water content is estimated, and an obstacle, which can mechanically be moved along the probe and which acts as a reference reflection for the TDR system with an exactly known position. Based on the known mechanical position of the reference reflection, the measured electrical position can be used as a measure for the effective dielectric constant of the environment. Thus, it is possible to determine the effective dielectric constant with a spatial resolution given by the step size of the obstacle displacement. A conventional industrial TDR-system, operating in the baseband, is used for the signal generation and for the evaluation of the pulse delay time of the obstacle reflection. Thus, a cost effective method for the acquisition of the dielectric measurement data is available.

scholarly journals Determination of ice-shelf bottom melting by time-domain reflectometry

1993 ◽  
Vol 39 (132) ◽  
pp. 353-356
Author(s):  
K. Grosfeld ◽  
N. Blindow
Keyword(s):  
Transmission Lines ◽  
Time Domain ◽  
High Reliability ◽  
Melting Rate ◽  
Time Domain Reflectometry ◽  
Ice Shelf ◽  
Wave Forms ◽  
A New Technique ◽  
Tape System

AbstractFor our work in the Filchner-Ronne Ice Shelf Programme (FRISP), we have developed a new technique for measuring the bottom-melting rate with high reliability. The method is based on time-domain reflectometry (TDR) measurements of transmission lines inserted into melt holes. The TDR-data are digitally recorded on magnetic tape. System resolution has been estimated at 0.2 m. Hence, re-measuring after 1 year gives an accuracy of 10% for melting rates of 2m a-1. Two transmission lines for TDR measurements were installed during the German FRIS Expedition 1989–90. This paper describes the design of the system. Examples of recorded wave forms are given.

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