Installation Guide Manual

Rockwell Automation Publication CNET-IN001C-EN-P - October 2011 79
Glossary
The following terms and abbreviations are used throughout this manual.
For definitions of terms not listed here, refer to the Allen-Bradley Industrial
Automation Glossary, publication AG-7.1
.
APD (avalanche photo diodes) Converts light to current in fiber receivers.
attenuation (loss) Ratio of input optical power to output optical power for a length of fiber optic
cable in dB/km.
bandwidth Pulse broadening caused by multi-mode dispersion and chromatic dispersion
within the cable.
baseband Information is transmitted through fiber by modulation of the optical power.
BER (bit error rate) Primary method of describing the data error rate. An acceptable error rate is
1 × 10
-9
bit errors (or 1 error in 1000 Mbits transmitted).
bend radius Maximum amount the cable can be bent and still function up to specification.
buffer Material surrounding the fiber (core, cladding, coating) that protects the fiber
from physical damage. Tight buffers are in direct contact with the fiber.
Loose-tube buffers provide a free environment for the fiber to float.
cladding Layer of material surrounding the core of a fiber.
coating Protective plastic material surrounding the cladding.
core Central cylinder of a fiber that is made of plastic or glass.
dB Unit of measure for loss or gain of power described as 10 × log (pout/pin).
dBM Power level referenced to 1 mw described as 10 × log (poptical/1 mw).
ferrite A passive electric component that is used to suppress high frequency noise in
electronic circuits.
graded index Fiber system where light travels in wave-like tracks to increase cable bandwidth.
insertion loss Loss in dB caused by the disruption of light when an object is inserted in the light
path (a connector, bulkhead, splice, or cable).
laser diode Converts electric energy into light energy to be coupled onto fiber media.
LED (light emitting diode) Converts electric energy into light.