EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 77)

OTDR 63
6 Testing Fibers in Advanced
Mode
Advanced mode offers all the tools you need to perform complete OTDR
tests and measurements manually and gives you control over all test
parameters.
Note: Most parameters can only be set if you select Advanced mode first. Once
you have finished selecting your settings, you can simply return to the test
mode you prefer.
By default, in Advanced mode, all available test wavelengths are selected.
In this mode, you can either set the acquisition parameters yourself or let
the application determine the most appropriate values.
In the latter case, the application will automatically evaluate the best
settings according to the fiber link currently connected to the unit:
³
The pulse width will be determined using a factory-defined
signal-to-noise ratio (SNR) requirement specified where the
End-of-Fiber (EoF) event has been detected.
The EoF event detection algorithm uses the end-of-fiber threshold
defined in the Acquisition tab of the application setup (for more
information, see Setting the Analysis Detection Thresholds on
page 167). If you are not sure about which value to choose, revert to
the factory default value for this parameter.
³
The range will then be set automatically. This optimum value may
differ from the values currently associated with the Distance dial of the
main window. In this case, the application will “add” the required
value and mark it with a * symbol.
³
The application uses the acquisition time defined in the Acquisition
tab of the application setup (for more information, see Setting the
Autorange Acquisition Time on page 68). The default value is
15 seconds. Longer acquisitions give better OTDR results.