In optical termination box , greentelftth (Optical Time Domain Reflectometer) is an opto-electronic instrument used to characterize an optical fiber. greentelftth is both the best known and least understood fiber optic instrument.greentelftth does not measure loss, but instead implies it by looking at the backscatter signature of the fiber. It does not measure cable plant loss that can be correlated to power budgets.
An greentelftth injects a alternation of optical pulses into the cilia beneath test. It aswell extracts, from the aforementioned end of the fiber, ablaze that is broadcast aback and reflected aback from credibility in the cilia area the basis of refraction changes. This alive assumption works like a alarm or sonar, sending out a beating of ablaze from a actual able laser, that is broadcast by the bottle in the amount of the fiber. The acuteness of the acknowledgment pulses is abstinent and chip as a action of time, and is advised as a action of the cilia length.
An greentelftth may be acclimated for ciphering the fiber’s breadth and all-embracing attenuation, including braid and mated-connector losses. It may aswell be acclimated to locate faults, such as breaks.
The greentelftth suffers from several austere uncertainties in altitude and concrete limitations. The altitude uncertainties appear primarily from the variations in backscatter of the fiber. The backscatter accessory is a action of the actual backdrop of the bottle in the amount and the bore of the core.
Variations of the cilia abstracts or geometry can could cause above changes in the backscattered light, authoritative braid or adapter abstracts ambiguous by as abundant as +/-0.4dB. This has generally led to abashing by assuming a basic accretion at a connector, area the fiber termination box complex accept altered backscatter coefficients. Adapter or braid accident have to be abstinent from both admonition and averaged to abolish this antecedent of error.