Performing an AUTOTEST
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Power-sum ACRN (ISO only)
Power-sum ACRF
Length & Delay
7.2
NEXT and RL Fault Locating
If the Locator option is enabled in the
Test Settings
Test Options
, WireXpert will display extremely
critical troubleshooting information in the form of a Time Domain Reflection plot for NEXT and Return
Loss.
Near-End Crosstalk (NEXT) is an undesired effect of interference between two pairs in a cable measured
at the same end of the cable as the interfering transmitter. In crosstalk, the signals traveling through
adjacent pairs of wire in twisted-pair cabling interfere with each other. Cross talk is undesirable.
The NEXT Locator displays the locations where crosstalk is excessive in the cable and indicates the exact
location in meters or feet from the LOCAL unit of where high crosstalk issue is seen. View individual plot
by selecting/deselecting cable pairs. Each two pairs of cables that have been tested for crosstalk are
represented by different color in the plot.
Return Loss (RL) is the measurement (in dB) of the amount of signal that is reflected back toward the
transmitter. Impedance mismatches and discontinuities caused by terminations to plugs or jacks and
within the plug/jack connection itself contributes to RL. Excessive bends and damaged cable will also
contribute to RL. The greater the variation in impedance, the greater the return loss reading.
The RL Locator displays the locations where return loss occurred during an AUTOTEST and indicates the
exact location of where the highest return loss occurs. View individual plot by selecting/deselecting
cable pair. Each pair of cables that has been tested is represented by different color in the plot.
Each peak result in NEXT and RL Locator could represent a new joint connection, rarely a coupler and
not necessary a bad cable that requires replacement.
