Triple-Play Service Deployment

Appendix A: PON Reflectometer Trace Analysis
This learning acquisition phase allows for the generation of a
reference pattern (RP) and an event reference table (ERT). The RP
corresponds to the trace, and the ERT includes the reflective and
nonreflective events list. The analysis does not require all of the
non-reflective events in order to run. After this phase, the analysis
can be performed using real conditions in the field.
Analysis Phase
Analysis can be performed during installation, monitoring, or
maintenance applications. During in service monitoring, if the
system detects an OTDR signature deviation, then analysis can be
performed. During maintenance, if a failure occurs during traffic,
then the fault location can be determined. In addition, the failure
level is established, if possible. In both cases, the analysis method
consists of a comparison between the current pattern (CP) and the
reference pattern (RP).
The following sections discuss the different events that can occur
during analysis.
Optical Branch Identification
During optical branch identification, two different possibilities
can appear:
1. Fresnel reflection extinction or attenuation
When analyzing the pattern comparison, if a fiber end
reflective event deviation is detected, then the affected optical
branch can be directly identified (Figure 3.28).
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