FTE-7000A User's Guide Rev A 5/2014
26
Chapter 7 OTDR Operation
Event Analysis Screen
Fib-R-Map
Schematic View
Event Table
Event Map
Trace Parameters
Fig 7.10
Sensitivity Settings
There are three levels of sensitivity for the event table and Fib-R-Map. (See Fig 7.4) To change the event
sensitivity, press the Menu button, use the left/right buttons to highlight the settings icon and press select. The
cursor is the yellow highlighted area. (If the yellow cursor is on a value that is the current selection, that block
will be highlighted green.) The setting highlighted in blue is the current setting. Use the LRUD buttons to
highlight the desired setting and press select. To exit the parameter screen, press the menu button.
The lowest setting possible should be used to help
fi
lter out any false events that may be caused by short pulse
widths, but are not true perturbations in the optical signal. High sensitivity presents events with loss down to
approximately 0.1dB, Medium (Md) with events down to approximately 0.2dB and Low (Lo) for event down to
about 0.5dB. Longer pulse widths, and averaging help to lower the number of false events. Highest sensitivity
settings should only be used for traces with high signal level, low noise, long pulse width and long average.
Macrobend Analysis
Macrobend analysis is performed with the dual trace operation and displayed in the event table. The traces
to be compared must have been performed at the same range and the primary trace must be of the longer
wavelength.
To conduct a macrobend analysis, open the
fi
le manager as described in chapter 9. Highlight the
fi
rst trace to
be loaded (the trace of the longer wavelength) and select to open. Open the
fi
le manager again and highlight
the trace to be compared (the trace of the short wavelength), open the drop-down menu under the
fi
le tab and
touch dual or use the up or down buttons to highlight dual and press select. Open the event analysis screen to
check for macrobends. If and event on the longer wavelength trace has 0.25db or greater loss than the same
event on the shorter wavelength trace, a macrobend event will be generated on the event table, identi
fi
ed by
a Macro label in the Type column. This event will immediately follow the event it is related to. For example:
If event number one was 5 dB at 1550nm and .5 db at 1310nm, the second event will be blank for location,
+4.5dB for splice, blank for 2point and DB/KM. The type
fi
eld will be listed as Macro.
To exit dual trace and macrobend analysis, simple start a new scan.
