EXFO FTB-7000 OTDR for FTB-200 v2 - Manual (Page 60)

Testing Fibers in Advanced Mode
46 FTB-7000 Series
Setting Distance Range, Pulse Width, and Acquisition Time
³
Time: corresponds to the acquisition duration (period during which
results will be averaged). Generally, longer acquisition times generate
cleaner traces (this is especially true with long-distance traces)
because as the acquisition time increases, more of the noise is
averaged out. This averaging increases the signal-to-noise ratio (SNR)
and the OTDR’s ability to detect small events.
The time settings will also determine how the timer (displayed in the
toolbar) counts time during testing (see Timer on page 20).
If the predefined values do not suit your needs, you can customize one
or all of them. For more information, see Customizing the Acquisition
Time Values on page 100.
In addition to the displayed values, the following time modes are
available:
³
Real: used to immediately view changes in the fiber under test. In
this mode, the SNR of the trace is lower and the trace is refreshed
instead of averaged until you press Stop.
You can alternate between real mode and averaging time interval
mode while an acquisition is in progress.
Note: The Real item will be available if only one wavelength is selected.
³
Auto: the application will use the autorange acquisition time that
you have previously defined (see Setting the Autorange Acquisition
Time on page 42). It will also evaluate the fiber type and length and
set the acquisition parameters accordingly.
You can use the same distance range, pulse width and acquisition time
parameters for testing at all wavelengths on a multiwavelength OTDR.
I
MPORTANT
To test using the high-resolution feature, the acquisition time must
be of at least 15 seconds.