EXFO MAX-700 - Manual (Page 321)

Maintenance
MAX-700 309
Verifying Your MAX-700
Verifying Your MAX-700
You can perform several tests to ensure your MAX-700 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 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.

30 ns
10 ns