Page 351 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

Tether jacket
+ Common return –
13.2 Transmission 343
(a)
(b)
(c)
path
Line length
Tether jacket
Line length
Tether jacket
Line length
–
+
+
–
–
+
+
–
–
+
FIGURE 13.15
Crosstalk. (a) Galvanic, (b) capacitive, and (c) inductive.
Signal
Tether jacket
Line length
NEXT
FEXT
FIGURE 13.16
Near end crosstalk versus far end crosstalk.
or NEXT) or to the far end (termed “far end crosstalk,” or FEXT). NEXT has little correlation to the tether/line length; however, the FEXT is directly proportional to the length of the line and forms a substantial problem in ROVs without proper wire shielding.
Twisted pair: A “balanced pair” wire set is a two-wire transmission line with two identical con- ductors having the same capacitance and leakage conductance to ground. The pair is electrically