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The Dam Safety Interest Group of CEA Technologies, Inc. (CEATI), a consortium of electrical power organizations, has applied Spread-spectrum time-domain reflectometry to identify potential faults in concrete dam anchor cables. The key benefit of Time Domain reflectometry over other testing methods is the non-destructive method of these tests. [10]
An OTDR. An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber.It is the optical equivalent of an electronic time domain reflectometer which measures the impedance of the cable or transmission line under test.
There are two basic principles of measurement for distributed sensing technology, OTDR (optical time-domain reflectometry) and OFDR (optical frequency-domain reflectometry). For distributed temperature sensing often a code correlation technology [ 2 ] [ 3 ] [ 4 ] is employed which carries elements from both principles.
In time-domain reflectometry (TDR), fast pulses are emitted, and the magnitude, duration and shape of the reflected pulses is analyzed. Frequency-domain reflectometry (FDR): [5] [6] this technique is based on the transmission of a set of stepped-frequency sine waves from the sample. As with TDR, these waves propagate to the sample and are ...
Time-domain thermoreflectance (TDTR) is a method by which the thermal properties of a material can be measured, most importantly thermal conductivity. This method can be applied most notably to thin film materials (up to hundreds of nanometers thick), which have properties that vary greatly when compared to the same materials in bulk.
Phase-sensitive coherent optical time-domain reflectometry (ϕ-OTDR) is a technique that can provide sufficient sensitivity and resolution for these distributed acoustic sensing systems. [2] Standard optical time-domain reflectometry techniques use light sources with coherence lengths, which are shorter than pulse lengths. This can yield a sum ...
Spread-spectrum time-domain reflectometry (SSTDR) is a measurement technique to identify faults, usually in electrical wires, by observing reflected spread spectrum signals. This type of time-domain reflectometry can be used in various high-noise and live environments. Additionally, SSTDR systems have the additional benefit of being able to ...
Stewart David Personick (born 1947) is an American researcher in telecommunications and computer networking.He worked at Bell Labs, TRW, and Bellcore (now Telcordia Technologies), researching optical fiber receiver design, propagation in multi-mode optical fibers, time-domain reflectometry, and the end-to-end modeling of fiber-optic communication systems.