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Electrical Transmission Lines
Published in Le Nguyen Binh, Wireless And Guided Wave Electromagnetics, 2017
A time-domain reflectometer (TDR) is an electronic instrument used to characterize and locate faults in metallic cables (for example, twisted wire pairs, coaxial cables). It can also be used to locate discontinuities in a connector, printed circuit board, or any other electrical path. The equivalent device for optical fiber is an optical time-domain reflectometer. The operation principle is based on the propagation time and reflection of short pulses generated at the sources and detection of reflected pulses from any discontinuities or impedance mismatches along the transmission lines.
Underground Distribution
Published in T. A. Short, Electric Power Distribution Handbook, 2018
Radar—Also called time-domain reflectometry (TDR), a radar set injects a very short-duration current pulse into the cable. At discontinuities, a portion of the pulse will reflect back to the set; knowing the velocity of wave propagation along cable gives us an estimate of the distance to the fault. Depending on the test set and settings, radar pulses can be from 5 ns to 5 μs wide. Narrower pulses give higher resolution, so users can better differentiate between faults and reflections from splices and other discontinuities (Banker et al., 1994).
Time and Frequency Domain Responses
Published in Wai-Kai Chen, Feedback, Nonlinear, and Distributed Circuits, 2018
Time-domain reflectometry (TDR) is used to characterize interconnections in the time domain. The setup essentially Consists of a time domain step generator and a digital sampling oscilloscope (Figure 17.1) [1]. The generator produces a positive-going step signal with a well-defined rise time. The step is applied to the device under test. The reflected and the transmitted signals are shown on the oscilloscope. Measuring the reflected signal is Called TDR; the transmitted signal is measured using the time-domain transmission (TDT) option.
Super-Resolution Time Domain Reflectometry Method for Microwave Imaging System Applications
Published in IETE Journal of Research, 2022
O. Mahdiyar, A. H. Mazinan, M. A. Pourmina, M. Naser-Moghaddasi
Time-Domain Reflectometry (TDR) method analysis is a well-known technique that is typically used to calculate the discontinuities along a microstrip line structure using Gaussian pulses. To improve the precision and accuracy of the TDR results, we have proposed using alternative technique, whereby a modified excitation pulse based on mixing double exponential pulse with a single-side linear frequency modulated signal is employed instead of the Gaussian stimulus signal in TDR. Using the conventional Gaussian signal typically leads to over 20% error in localization and 7.5% in amplitude voltage errors. The exponential signals produce significant improvement in localization error but more or less similar amplitude errors. JTFDR could lead to significant localization error almost same level like Gaussian, but are more accurate in determining reflected voltages amplitudes. Meanwhile, the proposed method delivers both precise localization within 0.4% better than exponential and very similar to JTFDR with 1.7% in voltage amplitude determination accuracy. The simulated results showed good agreement with the numerical prediction.