JDS Uniphase RX3 Series, Руководство пользователя

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Table 4: Initialized Operating State
Feature Function
Output
Channel 1
Source 1.3 laser
Measurement mode Backreflection
Averaging function Off
Data logging Off
Multidisplay mode Off
BR
0
Factory-set value
Setup Via loss (factory-set value)
Operating keys All keys that could be disabled are enabled
Any changes made to the BR or Power calibration are retained. Once initialized, the meter
displays the backreflection on channel 1 at 1310 nm.
The Initialize option can be locked out so that the last settings used are automatically restored
when the meter is powered on (see the
Customizing the Meter section).
Terminating a Fiber
Termination is a technique used to block all backreflections beyond a certain point in a network
of components. In all measurement testing, two terminations must be made:
The first (for measuring BR
0
) is made before the DUT, for example, on the meter side
The second (for measuring br
tot
) is made after the DUT
To minimize the errors associated with Rayleigh backscattering in the fiber, make both
termination points as close as possible to the DUT. The backreflection of all components and
connections between these two points is included in the equation for calculating the
backreflection value (BR) of the DUT.
High-attenuation bends in the fiber (for example, bends with a relatively small radius) remove all
backreflection and can be made anywhere along the length of the cable. When measuring
backreflection levels below -60 dB, in order to offset the small amount of reflection caused by
the high-attenuation bends, make low-attenuation bends (for example, bends with a relatively
large radius) just before the high-attenuation bends.
To terminate a fiber (single-mode fibers only):
1. Using the size of rod specified in the Inspection Report (see the
Customized Features and
Test Data section), wind the cable around the rod until the reading displayed on the meter
no longer changes (approximately six turns). To minimize any memory of the bends in the
cable jacket, do not pull on the cable while winding, and occasionally wind the cable in the
opposite direction.
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