EXFO CableSHARK P3 VF/DSL Cable Qualifier - Manual (Page 100)

VF / DSL Cable Qualifier
88
Cursor position =
Marker position =
Cursor / Marker Delta =
0.0 1250.0 2500.0 5000.0 3750.0
ZOOM IN
VERT MAIN
MENU
E F CHG
-1.000
-0.750
-0.500
-0.250
0.000
0.250
0.500
0.750
1.000
1998.7
0
1998.7
Pulse Width: ft
ft
300 ns
ZOOM IN
HORIZ SELECT
MARKER MORE AUTO
REPEAT
Reflections at ft(dBRL): 1998.7 (33.8+)
Cursor position =
Press or to move cursor
F IGURE 8.2.2.1B - R UNNING A M ANUAL TDR T EST WITH THE C ABLE E ND S HORTED
Typically any fault that produces a negative reflection indicates a low impedance. An example of a low
impedance fault is a short circuit.
Figure 8.2.2.1C shows the MANUAL TDR test result on a cable of 2500 ft with a bridge tap branch of 305 ft
connected at 2195 ft (Marker Line M) of the cable and the ends of the cable and the branch are open. The
distance from Marker Line (M) to Cursor Line (C) in the figure indicates the length of the bridge tap (about
305 feet).