Fluke DSP-4100 User Manual page 151

In cable, the inductive crosstalk component is very low. Most of the crosstalk is
due to the capacitive component. Because the difference between the two
components is nearly equal to the capacitive component, NEXT and FEXT are
nearly the same in a cable.
Because of how FEXT signals add up along a cable link, good ELFEXT
performance is critical for systems that transmit data over multiple wire pairs.
Examples of these systems are 100BASE-T4, 100VG-AnyLAN, and 1000BASE-T
(Gigabit Ethernet).
Signal
source
Resulting
NEXT signal B travels farther than A
NEXT
Signal
source
C
FEXT signals C and D travel the same distance
Figure 7-9. How FEXT Signals are All Equally Attenuated
A
(the length of the cable)
Basic Cabling Testing
FEXT and ELFEXT
B
D
Resulting
FEXT
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