VeEX OTDR FX150+ Series, Руководство пользователя

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OTDR Series e-Manual, D07-00- 076P -RevD00 Page 94 of 109
Span Begin and Span End
Refer to section Launch/Receive fiber offset.
The user can offset the length of an external launch fiber or patchcord, which is connected to
the fiber under test; otherwise, it becomes part of the fiber span and analysis. The launch fiber
can be offset or compensated in any of the following ways:
• Entering the known distance manually in km, meters, miles or feet.
• Entering the index # based on the event table.
•
Positioning the left marker at the event and pressing Span start in the right side column.
7.8.2 Saving OTDR Traces
The same procedure applies to offsetting Receiver fibers which are often used in Fiber to The
Antenna (FTTA) applications.
The FX300 and RXT OTDRs have a built-in launch fiber which is 40
meters in length. This fiber section will appear in grey color preceding
the first event. This internal launch fiber allows the user to characterize
the first connector of the fiber under test and evaluate its performance
(insertion loss and reflectance). The MTTplus OTDR has an optional
built-in launch fiber.
Using any of the above methods, the launch fiber can be offset and excluded from the fiber
span measurement.
Trace Information – Cables Launch Offset