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VMBR-1520 Mobile Broadband Router Installation, Operation, and Maintenance Guide
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D-1
Appendix D Glossary
The following acronyms and terms are used throughout this document.
10BASE-T -
a method of attaching devices to a local area network using unshielded twisted pair
wires and 8-contact telephone type modular connectors. Maximum line speed is 10 Mbit/s
100BASE-TX -
a method of attaching devices to a local area network using unshielded twisted pair
wires and 8-contact telephone type modular connectors. Maximum line speed is 100 Mbit/s
A/D -
analog to digital; process of converting electrical signals from analog waves to digital bits
A-PCMA
– Asymmetric Paired Carrier Multiple Access; a variant of the PCMA. The PCMA DSP
algorithm is only required for the hub and not required for the remote terminal. See PCMA
AC -
Alternating Current
ACU -
Antenna Control Unit; an electronic device that controls the pointing of the antenna based on
the location of the antenna relative to the satellite
AGC
– Automatic Gain Control; a circuit that monitors the input signal level and adjust its gain to
maintain a constant output signal amplitude
Antenna Subsystem (AS)
– consists of the antenna reflector, antenna feed, transmit amplifier,
receive low-noise amplifier, etc.
AS
- see Antenna Subsystem
ASCII -
American Standard Code for Information Interchange; a set of standard codes denoting
characters for information exchange between equipment from different manufacturers
AZ/EL -
Azimuth/Elevation for aiming antennas at satellite locations
Baseband Data
- a bit stream form of digital information as opposed to data in a waveform
BER
- Bit Error Rate
bit/s -
bits per second
BUC –
Block Up-converter; a device that converts a signal up to a block of frequencies in the super
high frequency range
°C
-
Celsius; a measure of temperature
CAT5 -
an Ethernet cable standard defined by the Electronic Industries Association and
Telecommunications Industry Association (commonly known as EIA/TIA-568). The cable consists of
four twisted pairs of copper wire terminated by a RJ-45 connector, supports 100 Mbit/s and a
maximum distance of 100 m
Characteristic Impedance
- A value of impedance (resistance and reactance) of a transmission line
measured over a frequency range that would exist if the line were infinite in length. The SI unit of
characteristic impedance is the ohm
CPU -
Central Processing Unit in a computer
CRC -
Cyclic Redundancy Check
CRMA
- Code Reuse Multiple Access; CRMA is a direct sequence spread spectrum technique used in
cellular telephony. A system using CRMA-based return channels has a throughput advantage by
enabling any terminal – or all terminals at once – to burst information to the hub at any time