480:
468:
798:
by measuring the time difference between when the impulse was sent and when the reflection returned. The sensors can output the analyzed level as a continuous analog signal or switch output signals. In TDR technology, the impulse velocity is primarily affected by the permittivity of the medium through which the pulse propagates, which can vary greatly by the moisture content and temperature of the medium. In many cases, this effect can be corrected without undue difficulty. In some cases, such as in boiling and/or high temperature environments, the correction can be difficult. In particular, determining the froth (foam) height and the collapsed liquid level in a frothy / boiling medium can be very difficult.
829:
strong relationship between the permittivity of a material and its water content, as demonstrated in the pioneering works of
Hoekstra and Delaney (1974) and Topp et al. (1980). Recent reviews and reference work on the subject include, Topp and Reynolds (1998), Noborio (2001), Pettinellia et al. (2002), Topp and Ferre (2002) and Robinson et al. (2003). The TDR method is a transmission line technique, and determines apparent permittivity (Ka) from the travel time of an electromagnetic wave that propagates along a transmission line, usually two or more parallel metal rods embedded in soil or sediment. The probes are typically between 10 and 30 cm long and connected to the TDR via coaxial cable.
842:
any point along a coaxial cable changes with deformation of the insulator between the conductors. A brittle grout surrounds the cable to translate earth movement into an abrupt cable deformation that shows up as a detectable peak in the reflectance trace. Until recently, the technique was relatively insensitive to small slope movements and could not be automated because it relied on human detection of changes in the reflectance trace over time. Farrington and
Sargand (2004) developed a simple signal processing technique using numerical derivatives to extract reliable indications of slope movement from the TDR data much earlier than by conventional interpretation.
444:
420:
456:
492:
432:
608:
the pulse encounters the short, no energy is absorbed at the far end. Instead, an inverted pulse reflects back from the short towards the launching end. It is only when this reflection finally reaches the launch point that the voltage at this point abruptly drops back to zero, signaling the presence of a short at the end of the cable. That is, the TDR has no indication that there is a short at the end of the cable until its emitted pulse can travel in the cable and the echo can return. It is only after this round-trip delay that the short can be detected by the TDR. With knowledge of the
408:
588:
574:
510:
562:
550:
538:
526:
101:
946:
479:
724:. This includes abrupt changes in the characteristic impedance. As an example, a trace width on a printed circuit board doubled at its midsection would constitute a discontinuity. Some of the energy will be reflected back to the driving source; the remaining energy will be transmitted. This is also known as a scattering junction.
886:
detection, localization and characterization of electrical defects (or mechanical defects having electrical consequences) in the wiring systems. Hard fault (short, open circuit) or intermittent defects can be detected very quickly increasing the reliability of wiring systems and improving their maintenance.
615:
A similar effect occurs if the far end of the cable is an open circuit (terminated into an infinite impedance). In this case, though, the reflection from the far end is polarized identically with the original pulse and adds to it rather than cancelling it out. So after a round-trip delay, the voltage
502:
These traces were produced by a commercial TDR using a step waveform with a 25 ps risetime, a sampling head with a 35 ps risetime, and an 18-inch (0.46 m) SMA cable. The far end of the SMA cable was left open or connected to different adapters. It takes about 3 ns for the pulse to
845:
Another application of TDRs in geotechnical engineering is to determine the soil moisture content. This can be done by placing the TDRs in different soil layers and measurement of the time of start of precipitation and the time that TDR indicate an increase in the soil moisture content. The depth of
828:
in soil and porous media. Over the last two decades, substantial advances have been made measuring moisture in soil, grain, food stuff, and sediment. The key to TDR's success is its ability to accurately determine the permittivity (dielectric constant) of a material from wave propagation, due to the
797:
device, the device generates an impulse that propagates down a thin waveguide (referred to as a probe) â typically a metal rod or a steel cable. When this impulse hits the surface of the medium to be measured, part of the impulse reflects back up the waveguide. The device determines the fluid level
607:
If the far end of the cable is shorted, that is, terminated with an impedance of zero ohms, and when the rising edge of the pulse is launched down the cable, the voltage at the launching point "steps up" to a given value instantly and the pulse begins propagating in the cable towards the short. When
878:
is used on aviation wiring for both preventive maintenance and fault location. Spread spectrum time domain reflectometry has the advantage of precisely locating the fault location within thousands of miles of aviation wiring. Additionally, this technology is worth considering for real time aviation
865:
Time domain reflectometry is used in semiconductor failure analysis as a non-destructive method for the location of defects in semiconductor device packages. The TDR provides an electrical signature of individual conductive traces in the device package, and is useful for determining the location of
332:
along the conductor; the resolution of such instruments is often the width of the pulse. Narrow pulses can offer good resolution, but they have high frequency signal components that are attenuated in long cables. The shape of the pulse is often a half cycle sinusoid. For longer cables, wider pulse
841:
settings including highway cuts, rail beds, and open pit mines (Dowding & O'Connor, 1984, 2000a, 2000b; Kane & Beck, 1999). In stability monitoring applications using TDR, a coaxial cable is installed in a vertical borehole passing through the region of concern. The electrical impedance at
389:(SSTDR) is used to detect intermittent faults in complex and high-noise systems such as aircraft wiring. Coherent optical time domain reflectometry (COTDR) is another variant, used in optical systems, in which the returned signal is mixed with a local oscillator and then filtered to reduce noise.
885:
Multi carrier time domain reflectometry (MCTDR) has also been identified as a promising method for embedded EWIS diagnosis or troubleshooting tools. Based on the injection of a multicarrier signal (respecting EMC and harmless for the wires), this smart technology provides information for the
297:
Generally, the reflections will have the same shape as the incident signal, but their sign and magnitude depend on the change in impedance level. If there is a step increase in the impedance, then the reflection will have the same sign as the incident signal; if there is a step decrease in
491:
93:, then there will be no reflections and the remaining incident signal will be absorbed at the far-end by the termination. Instead, if there are impedance variations, then some of the incident signal will be reflected back to the source. A TDR is similar in principle to
1320:
Duncan, D.; Trabold, T.A.; Mohr, C.L.; Berrett, M.K. "MEASUREMENT OF LOCAL VOID FRACTION AT ELEVATED TEMPERATURE AND PRESSURE". Third World
Conference on Experimental Heat Transfer, Fluid Mechanics and Thermodynamics, Honolulu, Hawaii, USA, 31 October-5 November 1993.
503:
travel down the cable, reflect, and reach the sampling head. A second reflection (at about 6 ns) can be seen in some traces; it is due to the reflection seeing a small mismatch at the sampling head and causing another "incident" wave to travel down the cable.
623:
The magnitude of the reflection is referred to as the reflection coefficient or Ï. The coefficient ranges from 1 (open circuit) to â1 (short circuit). The value of zero means that there is no reflection. The reflection coefficient is calculated as follows:
619:
Perfect termination at the far end of the cable would entirely absorb the applied pulse without causing any reflection, rendering the determination of the actual length of the cable impossible. In practice, some small reflection is nearly always observed.
1232:
Robinson, D. A., C. S. Campbell, J. W. Hopmans, B. K. Hornbuckle, Scott B. Jones, R. Knight, F. Ogden, J. Selker, and O. Wendroth, 2008. "Soil moisture measurement for ecological and hydrological watershed-scale observatories: A review."
1313:
Scarpetta, M.; Spadavecchia, M.; Adamo, F.; Ragolia, M.A.; Giaquinto, N. âłDetection and
Characterization of Multiple Discontinuities in Cables with Time-Domain Reflectometry and Convolutional Neural Networksâł. Sensors 2021, 21, 8032.
160:
and the subsequent observation of the energy reflected by the system. By analyzing the magnitude, duration and shape of the reflected waveform, the nature of the impedance variation in the transmission system can be determined.
950:
172:
is applied, a step signal is observed on the display, and its height is a function of the resistance. The magnitude of the step produced by the resistive load may be expressed as a fraction of the input signal as given by:
340:
steps are also used. Instead of looking for the reflection of a complete pulse, the instrument is concerned with the rising edge, which can be very fast. A 1970s technology TDR used steps with a rise time of 25 ps.
1426:
467:
587:
509:
443:
732:
Time domain reflectometers are commonly used for in-place testing of very long cable runs, where it is impractical to dig up or remove what may be a kilometers-long cable. They are indispensable for
701:
250:
485:
TDR trace of a transmission line terminated on an oscilloscope high impedance input. The blue trace is the pulse as seen at the far end. It is offset so that the baseline of each channel is visible
455:
374:) is an analogous technique that measures the transmitted (rather than reflected) impulse. Together, they provide a powerful means of analysing electrical or optical transmission media such as
1419:
1222:
Robinson D.A., S.B. Jones, J.M. Wraith, D. Or and S.P. Friedman, 2003 "A review of advances in dielectric and electrical conductivity measurements in soils using time domain reflectometry".
819:
785:
packages to measuring liquid levels. In the former, the time domain reflectometer is used to isolate failing sites in the same. The latter is primarily limited to the process industry.
298:
impedance, the reflection will have the opposite sign. The magnitude of the reflection depends not only on the amount of the impedance change, but also upon the loss in the conductor.
1212:
Pettinelli E., A. Cereti, A. Galli, and F. Bella, 2002. "Time domain reflectometry: Calibration techniques for accurate measurement of the dielectric properties of various materials".
497:
TDR trace of a transmission line terminated on an oscilloscope high impedance input driven by a step input from a matched source. The blue trace is the signal as seen at the far end.
1412:
1113:
1043:
1435:
810:
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.
431:
419:
1374:
1136:
1199:
and M. Schmidt. "Analysis of
Reflectometry for Detection of Chafed Aircraft Wiring Insulation". Department of Electrical and Computer Engineering. Utah State University.
573:
988:
1983 Tektronix
Catalog, pages 140â141, the 1502 uses a step (system rise time less than 140 ps), has a resolution of 0.6 inch and a range of 2,000 feet.
752:
leakage as it degrades and absorbs moisture, long before either leads to catastrophic failures. Using a TDR, it is possible to pinpoint a fault to within centimetres.
279:
81:
A TDR measures reflections along a conductor. In order to measure those reflections, the TDR will transmit an incident signal onto the conductor and listen for its
397:
These traces were produced by a time-domain reflectometer made from common lab equipment connected to approximately 100 feet (30 m) of coaxial cable having a
31:
407:
763:. The slight change in line impedance caused by the introduction of a tap or splice will show up on the screen of a TDR when connected to a phone line.
875:
807:
386:
345:
756:
1240:
Topp G.C., J.L. Davis and A.P. Annan, 1980. "Electromagnetic determination of soil water content: measurements in coaxial transmission lines".
629:
178:
1182:
1355:
1110:
1040:
846:
the TDR (d) is a known factor and the other is the time it takes the drop of water to reach that depth (t); therefore the speed of water
561:
525:
549:
537:
1677:
910:
113:
1133:
979:
1983 Tektronix
Catalog, pages 140â141, the 1503 uses "1/2-sine-shaped pulses" and has a 3-foot resolution and a range of 50,000 feet.
1304:
1068:
915:
361:
1383:
1153:
1287:
Farrington, S.P. and
Sargand, S.M., "Advanced Processing of Time Domain Reflectometry for Improved Slope Stability Monitoring",
1687:
961:
955:
806:
The Dam Safety
Interest Group of CEA Technologies, Inc. (CEATI), a consortium of electrical power organizations, has applied
1250:
Topp G.C. and W.D. Reynolds, 1998. "Time domain reflectometry: a seminal technique for measuring mass and energy in soil".
1093:
1585:
1202:
Noborio K. 2001. "Measurement of soil water content and electrical conductivity by time domain reflectometry: A review".
850:(v) can be determined. This is a good method to assess the effectiveness of Best Management Practices (BMPs) in reducing
1631:
1534:
1334:
1152:
G.Millet, S.Bruillot, D.Dejardin, N.Imbert, F.Auzanneau, L.Incarbone, M.Olivas, L.Vincent, A.Cremzi, S.Poignant, 2014.
305:
to the TDR and displayed or plotted as a function of time. Alternatively, the display can be read as a function of
905:
1636:
1529:
312:
Because of its sensitivity to impedance variations, a TDR may be used to verify cable impedance characteristics,
129:
58:
1393:
1280:
Kane, W.F. & Beck, T.J. 1999. "Advances in Slope
Instrumentation: TDR and Remote Data Acquisition Systems".
401:
of 50 ohms. The propagation velocity of this cable is approximately 66% of the speed of light in a vacuum.
1322:
847:
838:
398:
282:
895:
609:
30:
1656:
737:
733:
90:
1274:
Dowding, C.H. & O'Connor, K.M. 2000b. "Real Time Monitoring of Infrastructure using TDR Technology".
1682:
1484:
749:
70:
1267:
Dowding, C.H. & O'Connor, K.M. 2000a. "Comparison of TDR and Inclinometers for Slope Monitoring".
1167:
Hoekstra, P. and A. Delaney, 1974. "Dielectric properties of soils at UHF and microwave frequencies".
1509:
1399:
1282:
Field Measurements in Geomechanics, 5th International Symposium on Field Measurements in Geomechanics
1264:. (Ed. J.H. Dane and G.C. Topp), SSSA Book Series No. 5. Soil Science Society of America, Madison WI.
741:
317:
109:
86:
925:
309:
length because the speed of signal propagation is almost constant for a given transmission medium.
344:
Still other TDRs transmit complex signals and detect reflections with correlation techniques. See
1641:
900:
782:
1404:
1346:
1600:
1539:
1469:
1464:
1454:
1300:
1064:
794:
771:
760:
714:
286:
136:. The total rise time consists of the combined rise time of the driving pulse and that of the
82:
55:
51:
781:
The TDR principle is used in industrial settings, in situations as diverse as the testing of
1651:
1605:
825:
767:
306:
35:
837:
Time domain reflectometry has also been utilized to monitor slope movement in a variety of
257:
1646:
1595:
1459:
1117:
1094:
Feasibility of Reflectometry for Nondestructive Evaluation of Prestressed Concrete Anchors
1047:
775:
313:
17:
778:
device can be detected. Short circuited pins can also be detected in a similar fashion.
1580:
854:
770:
of modern high-frequency printed circuit boards with signal traces crafted to emulate
100:
1671:
1196:
1178:
1140:
1129:
1106:
1089:
1036:
379:
375:
357:
169:
149:
66:
1340:
882:
This method has been shown to be useful to locating intermittent electrical faults.
61:. It can be used to characterize and locate faults in metallic cables (for example,
1590:
1575:
1474:
965:
302:
137:
62:
1610:
1544:
1514:
1494:
920:
1039:
and Gunther, Jacob. "Analysis of Spread Spectrum Time Domain Reflectometry for
720:
Any discontinuity can be viewed as a termination impedance and substituted as Z
612:
in the particular cable-under-test, the distance to the short can be measured.
1615:
1504:
1489:
851:
1183:
Analysis of spread spectrum time domain reflectometry for wire fault location
879:
monitoring, as spread spectrum reflectometry can be employed on live wires.
1554:
1549:
1479:
1323:
https://www.mohr-engineering.com/guided-radar-liquid-level-documents-EFP.php
997:
1983 Tektronix Catalog, page 289, S-52 pulse generator has a 25-ps risetime.
745:
337:
133:
117:
709:
is defined as the characteristic impedance of the transmission medium and Z
1559:
1499:
1134:
Feasibility of Spread Spectrum Sensors for Location of Arcs on Live Wires
165:
121:
1289:
Proceedings of the Eleventh Annual Conference on Tailings and Mine Waste
1519:
1449:
1295:
Smolyansky, D. (2004). "Electronic Package Fault Isolation Using TDR".
50:) is an electronic instrument used to determine the characteristics of
593:
TDR of step into mated BNC connector pair; the peak reflection is 0.04
515:
TDR of step into disconnected SMA male connector (non-precision open)
157:
153:
132:
takes to return. The limitation of this method is the minimum system
1315:
1096:," IEEE Journal of Sensors, Vol. 9. No. 11, Nov. 2009, pp. 1322â1329
1354:, Application Note, Keysight Technologies, 31 May 2013, AN-1304-2,
616:
at the TDR abruptly jumps to twice the originally-applied voltage.
329:
99:
94:
29:
1109:, and J. Gunther, 2005. "Analysis of spread spectrum time domain
473:
TDR trace of a transmission line with an almost ideal termination
461:
TDR trace of a transmission line with a 1nF capacitor termination
449:
TDR trace of a transmission line with a short circuit termination
104:
Signal (or energy) transmitted and reflected from a discontinuity
125:
1408:
1382:, Application Note, AEA Technology, Inc., AN201, archived from
1010:, Instruction Manual, Beaverton, OR: Tektronix, September 1982
1025:, Instruction Manual, Beaverton, OR: Tektronix, November 1971
320:
locations and associated losses, and estimate cable lengths.
124:
to the reflecting impedance can also be determined from the
1012:
First printing is 1982, but copyright notice includes 1971.
820:
Measuring moisture content using time-domain reflectometry
759:, where they help determine the existence and location of
713:
is the impedance of the termination at the far end of the
328:
TDRs use different incident signals. Some TDRs transmit a
437:
TDR trace of a transmission line with an open termination
696:{\displaystyle \rho ={\frac {Z_{t}-Z_{o}}{Z_{t}+Z_{o}}}}
245:{\displaystyle \rho ={\frac {R_{L}-Z_{0}}{R_{L}+Z_{0}}}}
1269:
Geotechnical MeasurementsâProceedings of Geo-Denver2000
1260:
Topp, G.C. and T.P.A. Ferre, 2002. "Water content", in
774:. By observing reflections, any unsoldered pins of a
632:
260:
181:
1624:
1568:
1442:
1276:
Structural Materials Technology NDT Conference 2000
168:is placed on the output of the reflectometer and a
695:
273:
244:
148:The TDR analysis begins with the propagation of a
69:), and to locate discontinuities in a connector,
766:TDR equipment is also an essential tool in the
531:TDR of step into disconnected APC-7mm connector
1154:"Aircraft Electrical Wiring Monitoring System"
1132:, Smith, P., Safavi, Mehdi, and M. Lo, Chet. "
740:, as TDRs can detect resistance on joints and
1436:Electrical and electronic measuring equipment
1420:
8:
814:Used in the earth and agricultural sciences
1427:
1413:
1405:
1080:Hamilton Avnet part number P-3636-603-5215
140:or sampler that monitors the reflections.
1396:â TDR for Microwave/RF and Digital Cables
876:spread-spectrum time-domain reflectometry
808:Spread-spectrum time-domain reflectometry
684:
671:
659:
646:
639:
631:
387:spread-spectrum time-domain reflectometry
346:spread-spectrum time-domain reflectometry
265:
259:
233:
220:
208:
195:
188:
180:
1204:Computers and Electronics in Agriculture
1050:." IEEE Sensors Journal. December, 2005.
874:Time domain reflectometry, specifically
567:TDR of step into APC-7mm precision short
1299:. ASM International. pp. 289â302.
1143:". IEEE Sensors Journal. December 2005.
936:
757:technical surveillance counter-measures
579:TDR of step into APC-7mm precision open
555:TDR of step into APC-7mm precision load
543:TDR of step into APC-7mm precision open
505:
403:
385:Variations of TDR exist. For example,
1373:DeWinter, Paul; Ashley, Bill (2011),
1111:reflectometry for wire fault location
7:
1120:". IEEE Sensors Journal 5:1469â1478.
1061:Undersea Fiber Communication Systems
755:TDRs are also very useful tools for
301:The reflections are measured at the
1361:from the original on 9 October 2022
85:. If the conductor is of a uniform
425:Simple TDR made from lab equipment
413:Simple TDR made from lab equipment
25:
1341:Work begins to repair severed net
1316:https://doi.org/10.3390/s21238032
1297:Microelectronics Failure Analysis
916:Optical time-domain reflectometer
362:optical time-domain reflectometer
1348:Time Domain Reflectometry Theory
1335:Radiodetection Extended Training
1262:Methods of Soil Analysis. Part 4
1214:Review of Scientific Instruments
949: This article incorporates
944:
861:In semiconductor device analysis
586:
572:
560:
548:
536:
524:
508:
490:
478:
466:
454:
442:
430:
418:
406:
73:, or any other electrical path.
1169:Journal of Geophysical Research
962:General Services Administration
870:In aviation wiring maintenance
34:Time-domain reflectometer for
1:
1400:TDR vs FDR: Distance to Fault
802:Used in anchor cables in dams
597:vertical: 20 mρ/div
519:vertical: 0.5 ρ/div
120:of the reflected signal. The
1632:Arbitrary waveform generator
1535:Transformer ratio arm bridge
1376:Step vs Pulse TDR Technology
833:In geotechnical engineering
824:A TDR is used to determine
595:horizontal: 200 ps/div
368:Time-domain transmissometry
116:can be determined from the
1704:
1063:, Elsevier Science, 2002,
906:Noise-domain reflectometry
817:
581:horizontal: 20 ps/div
356:The equivalent device for
1678:Electronic test equipment
1637:Digital pattern generator
1530:Time-to-digital converter
1525:Time-domain reflectometer
1181:, and J. Gunther, 2005. "
1092:, P. Smith, M. Diamond, "
911:NicolsonâRossâWeir method
517:horizontal: 1 ns/div
352:Variations and extensions
44:time-domain reflectometer
18:Time-domain reflectometry
1242:Water Resources Research
610:signal propagation speed
399:characteristic impedance
283:characteristic impedance
896:Frequency domain sensor
738:telecommunication lines
1688:Semiconductor analysis
1657:Video-signal generator
1394:TDR for Digital Cables
957:Federal Standard 1037C
951:public domain material
734:preventive maintenance
697:
275:
246:
105:
39:
1485:Microwave power meter
1284:: 101â105. Singapore.
1252:Soil Tillage Research
698:
276:
274:{\displaystyle Z_{0}}
247:
103:
71:printed circuit board
33:
27:Electronic instrument
1510:Peak programme meter
1271:: 80â81. Denver, CO.
1187:IEEE Sensors Journal
1059:José Chesnoy (ed.),
789:In level measurement
630:
258:
179:
1235:Vadose Zone Journal
1224:Vadose Zone Journal
1041:Wire Fault Location
926:Standing wave ratio
1642:Function generator
1116:2010-12-31 at the
1046:2010-12-31 at the
901:Murray loop bridge
866:opens and shorts.
783:integrated circuit
772:transmission lines
693:
271:
242:
106:
40:
1665:
1664:
1601:Spectrum analyzer
1540:Transistor tester
1470:Frequency counter
1465:Electricity meter
1455:Capacitance meter
1008:S-6 Sampling Head
795:level measurement
748:, and increasing
715:transmission line
691:
333:widths are used.
287:transmission line
240:
16:(Redirected from
1695:
1652:Signal generator
1606:Waveform monitor
1586:Network analyzer
1429:
1422:
1415:
1406:
1390:
1388:
1381:
1369:
1368:
1366:
1360:
1353:
1337:â ABC's of TDR's
1310:
1291:, October, 2004.
1156:
1150:
1144:
1127:
1121:
1103:
1097:
1087:
1081:
1078:
1072:
1057:
1051:
1033:
1027:
1026:
1023:7S12 TDR/Sampler
1019:
1013:
1011:
1004:
998:
995:
989:
986:
980:
977:
971:
970:
969:
964:. Archived from
948:
947:
941:
826:moisture content
768:failure analysis
702:
700:
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694:
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689:
688:
676:
675:
665:
664:
663:
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89:and is properly
52:electrical lines
21:
1703:
1702:
1698:
1697:
1696:
1694:
1693:
1692:
1668:
1667:
1666:
1661:
1647:Sweep generator
1620:
1596:Signal analyzer
1564:
1460:Distortionmeter
1438:
1433:
1386:
1379:
1372:
1364:
1362:
1358:
1351:
1345:
1331:
1307:
1294:
1164:
1162:Further reading
1159:
1151:
1147:
1128:
1124:
1118:Wayback Machine
1104:
1100:
1088:
1084:
1079:
1075:
1071:, p.171 (COTDR)
1058:
1054:
1048:Wayback Machine
1034:
1030:
1021:
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1016:
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954:
945:
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942:
938:
934:
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835:
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804:
793:In a TDR-based
791:
776:ball grid array
730:
723:
712:
708:
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1581:Logic analyzer
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1195:Waddoups, B.,
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1139:2010-05-01 at
1130:Furse, Cynthia
1122:
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1037:Furse, Cynthia
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968:on 2022-01-22.
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855:surface runoff
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818:Main article:
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1389:on 2014-08-26
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1035:Smith, Paul,
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67:coaxial cable
64:
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54:by observing
53:
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37:
32:
19:
1683:Soil physics
1591:Oscilloscope
1576:Bus analyzer
1524:
1475:Galvanometer
1384:the original
1375:
1363:, retrieved
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966:the original
956:
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848:infiltration
844:
839:geotechnical
836:
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138:oscilloscope
107:
80:
63:twisted pair
47:
43:
41:
1611:Vectorscope
1545:Tube tester
1515:Psophometer
1495:Megohmmeter
1365:13 February
1237:7: 358-389.
1219::3553â3562.
1192::1469â1478.
1177:Smith, P.,
1174::1699â1708.
1105:Smith, P.,
921:Return loss
603:Explanation
170:step signal
83:reflections
77:Description
1672:Categories
1625:Generation
1616:Videoscope
1505:Peak meter
1490:Multimeter
1229:: 444â475.
932:References
852:stormwater
750:insulation
742:connectors
293:Reflection
164:If a pure
91:terminated
1555:Voltmeter
1550:Wattmeter
1480:LCR meter
1257::125â132.
1247::574â582.
1209::213â237.
761:wire taps
653:−
634:ρ
338:rise time
318:connector
202:−
183:ρ
134:rise time
118:amplitude
110:impedance
87:impedance
56:reflected
1569:Analysis
1560:VU meter
1500:Ohmmeter
1443:Metering
1356:archived
1197:C. Furse
1179:C. Furse
1137:Archived
1114:Archived
1107:C. Furse
1090:C. Furse
1044:Archived
890:See also
744:as they
122:distance
65:wire or
1520:Q meter
1450:Ammeter
746:corrode
705:Where Z
285:of the
281:is the
156:into a
128:that a
112:of the
1303:
1067:
360:is an
314:splice
254:where
158:system
154:energy
144:Method
59:pulses
1387:(PDF)
1380:(PDF)
1359:(PDF)
1352:(PDF)
953:from
728:Usage
336:Fast
330:pulse
307:cable
130:pulse
95:radar
36:cable
1367:2012
1301:ISBN
1065:ISBN
378:and
316:and
150:step
126:time
108:The
1185:".
736:of
372:TDT
48:TDR
1674::
1255:47
1245:16
1217:73
1207:31
1172:79
960:.
857:.
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42:A
1428:e
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1309:.
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722:t
711:t
707:o
686:o
682:Z
678:+
673:t
669:Z
661:o
657:Z
648:t
644:Z
637:=
370:(
267:0
263:Z
235:0
231:Z
227:+
222:L
218:R
210:0
206:Z
197:L
193:R
186:=
46:(
20:)
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