Verifying your otdr – EXFO FTB-7000 OTDR for FTB-200 v2 User Manual
Page 284
Maintenance
270
FTB-7000 Series
Verifying Your OTDR
Verifying Your OTDR
You can perform several tests to ensure your OTDR operates within
specifications.
Deviation is measured to determine if the OTDR needs recalibration.
Setting your OTDR to zero can only be done at EXFO. However, you can
test your OTDR to verify the accuracy of its measurement origin.
To measure the deviation:
1. Connect at least 2 km of fiber to the OTDR output port.
2. Set the distance range at 2.5 km and acquisition time at 180 seconds.
3. Measure the deviation between a 10 ns pulse and a 30 ns pulse for
each laser.
The deviation (Δ) should be between 2.0 dB and 3.0 dB. The deviation must
be measured in the linear backscatter region. Do not measure the
deviation near distinct reflections.
Performance will be affected if the observed deviation is beyond these
limits. The OTDR will eventually require a factory calibration.
Note: This does not affect the precision of distance or loss measurements.
Δ
30 ns
10 ns