Chapter 6: Diagnose Copper Test Failures
The HDTDR Analyzer
199
The horizontal scale shows the distance along the cabling.
Tap to see help for this screen.
The Value is the percentage of the signal reflected at the
cursor’s location.
The tester adjusts the values for insertion loss so that they show
the amplitudes of the signals at the sources of the reflections.
The margin is the difference between the measured value and
the 15% reflection limit. The margin is negative if the value
exceeds the limit.
The HDTDR plot for coaxial cable includes limit lines and a PASS/
FAIL result. The lines are fixed at 15%. The tester uses these limits
to give the test a PASS/FAIL result. Figure 87 shows a reflection
at 31.3 m that exceeds the limit. The reflection was caused by a
50 cable connected a 75 cable.
To zoom in and out, use the pinch, reverse-pinch, and
double-tap gestures on the touchscreen. You can also use
the zoom controls to change the magnification on the
distance and amplitude scales independently. See Figure 5
on page 24.
Note
For HDTDR plots for short cables such as patch cords,
the tester does not change the magnification for the
distance (horizontal) scale.
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