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Pass/fail tests – EXFO OTDR 2 User Manual

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Description of Event Types

196

OTDR

Merged Event

Pass/Fail Tests

As an example about pass/fail tests, let us consider the situation below:

For a merged event, it is possible to determine the global event loss, but not
the contribution of each sub-event. This is why the pass/fail test may
sometimes lead to “false positive” or “false negative” results.

When evaluating event status against thresholds, we are faced with two
possible conditions:

All event types are tested (reflective, non-reflective)

Only some event types are selected (for example, you could decide not
to test reflective loss)

The third case would be to test none of the event types, which means the
same as not wanting to know the status of the events.

Merged sub-events:

2 reflective losses
1 non-reflective loss

Thresholds:

Reflective loss: 0.5 dB
Non-reflective Loss: 0.2 dB

Merged event

Event loss