ASD FieldSpec 3, User Manual

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© 2010 ASD Inc. 29 FieldSpec® 3 User Manual
Chapter 4 Fiberoptic Interface
ASD offers a variety of fiberoptic cable lengths to interface with the
FieldSpec spectroradiometer. These fiberoptic cables are used for reflectance,
transmittance, radiance, or irradiance measurements.
The fiberoptic cable is routed straight through the front panel to the
spectrometer. The FieldSpec spectroradiometer is able to accurately measure
radiance and irradiance in absolute units, because there is no front panel
connector to add uncertainty in the throughput of the instrument.
fiberoptic cables should be loosely coiled and stored in the compartments
provided. All accessories should be stored in the designated compartments of
the carrier or in a separate protective case.
4.1 Fiberoptic Cables
The Fiberoptic cable is made up of fifty-seven (57) randomly distributed glass
fibers. Nineteen (19) of these fibers are 100-micron and are distributed to the
VNIR region. The remaining thirty-eight (38) fibers are 200-micron and are
evenly divided between the two SWIR regions. All fifty-seven fibers are
housed in a plastic sheath. A standard cable has a diameter of 0.19 inches and
is an f2 cable.
The fibers are protected by a metal spiral inside the black cable casing. If
there are kinks in the cable, the fibers are not necessarily damaged. If,
however, the cable has been crunched so severely that the protective metal
spiral can be seen, the chances are high that the fibers have also been
damaged. Each broken fiber results in a ~5% loss of response.
WARNING! The Fiberoptic cable should never be stored with a bend of less than a 5"
diameter for long periods of time.