HP 54750A, Руководство пользователя, Страница: 25 / 478

Inspection Visual inspection
Although it is not necessary , visual inspection of ber ends can be helpful.
Contamination and/or imperfections on the cable endface can be detected as
well as cracks or chips in the ber itself.
Several ber inspection scopes are on the market, but any microscope with
an enlargement range of 100X to 200X can be used. It is helpful to devise
some method to hold the ber in place while viewing in this range .
Inspect the entire endface for contamination, raised metal, or dents in the
metal, as well as any other imperfections . Inspect the ber core for cracks
and chips .
Visible imperfections not touching the ber core may not aect the
performance of the lightwave connection (unless the imperfections keep
the bers from contacting). Consistent optical measurements are the best
assurance that your lightwave connection is performing properly .
Optical performance
testing
Introduction
Consistent measurements with your lightwave equipment are a good
indication that you have good connections . However , you may wish to know
the insertion loss and/or return loss of your lightwave cables or accessories . If
you test your cables and accessories for insertion loss and return loss upon
receipt, and retain the measured data for comparison, you will be able to tell
in the future if any degradation has occurred.
Insertion loss
Insertion loss can be tested using a number of dierent test equipment
congurations . Some of these are:
an HP 8702B or HP 8703A lightwave component analyzer system with a
lightwave source and receivers
an HP 83420 lightwave test set with an HP 8510 network analyzer
an HP 8153A lightwave multimeter with a source and a power sensor
module
Many other possibilities exist. The basic requirements are an appropriate
lightwave source and a compatible lightwave receiver . Refer to the manuals
provided with your lightwave test equipment for information on how to
perform an insertion loss test.
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