Fluke DTX Series - Propagation Delay and Delay Skew

Certifying Twisted Pair Cabling
Twisted Pair Autotest Results 3
3-17
Propagation Delay and Delay Skew
Propagation delay is the time taken for a test pulse to
travel the length of a cable pair. The delay is measured in
nanoseconds. Propagation delays vary slightly among
pairs because of small differences in electrical
characteristics and length.
Delay skews are the differences in propagation delays
between the shortest delay and the delays of the other
cable pairs. The shortest delay is shown as “0 ns” in the
delay skew results.
The propagation delay and delay skew results show a
limit if the measurements required by the selected test
limit. Otherwise, the results always show PASS. Figure
3-11 shows the propagation delay and delay skew results
screens.
Pair with the shortest electrical length
is usually the shortest pair
amd88f.eps
Figure 3-11. Propagation Delay and Delay Skew Results