Fluke DTX-1800, Technical Reference Handbook

Page: 109 / 398

Certifying Twisted Pair Cabling
Twisted Pair Autotest Results
3-23
3
Figure 3-17. NEXT Plot
amd07f.eps
A
The location of the NEXT results. Press
J
to switch
between the tester and smart remote.
B
The overall NEXT result. “PASS*/FAIL* Results” on page 3-12
describes results marked with an asterisk.
C
Horizontal and vertical magnification levels for the plot. To
change the magnification, press
K
Change To Zoom; then
use
BC
or
AD
to zoom horizontally or vertically.
D
Measured NEXT for the cable pairs. Higher NEXT means
better cabling performance.
E
The limit line (in red) for NEXT. The higher the measurements
rise above the limit line, the better the cabling performance.
If the line is black, NEXT is not evaluated at those frequencies.
See page 3-13. Press
L
to see plots of individual pairs.
F
The cursor and its location on the frequency scale. When you
first view the plot, the cursor is placed at the worst margin.
Use
BC
to move the cursor (if the plot is in zoom mode,
press
K
Change To Cursor first).
G
The measured NEXT and margin at the cursor’s position.
Margin is the difference between the measured value and
the limit. Margin is negative if the pair failed.
H
The horizontal scale is the frequency range in megahertz. The
vertical scale is the NEXT range in decibels.
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