Black Box Scan-LAN 80, Руководство пользователя

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69
GLOSSARY
but because the transmission circuit is split between
two twisted pairs, excessive crosstalk occurs.
TDR (Time-Domain Reflectometry) — A technique
for measuring cable lengths by timing the duration
between an incident test pulse and the reflected
pulse from an impedance mismatch on the cable
(such as an open at the end of the cable). The
length of the cable may be calculated by knowing
the velocity of propagation of the pulse through
the cable:
Length=1/2t x NVP x C
Where: t=round-trip time between incident and
reflected pulses.
NVP=nominal velocity of propagation
of electrical signals in the cable.
C=speed of light in a vacuum.
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Split Pairs