05-3946A01, Rev. C
TransNET OEM Integration Guide
G-1
GLOSSARY
Antenna System Gain—
A figure, normally expressed in dB, representing
the power increase resulting from the use of a gain-type antenna. System
losses (from the feedline and coaxial connectors, for example) are subtracted
from this figure to calculate the total antenna system gain.
ARQ—
Automatic Repeat Request. An error-correction technique whereby
flawed data packets are detected and a request for re-transmission is issued.
Bit—
The smallest unit of digital data, often represented by a one or a zero.
Eight bits (plus start, stop, and parity bits) usually comprise a byte.
Bits-per-second—
See BPS.
BPS—
Bits-per-second. A measure of the information transfer rate of digital
data across a communication channel.
Byte—
A string of digital data usually made up of eight data bits and start,
stop, and parity bits.
Cyclic Redundancy Check (CRC)
—A method to detect and correct errors
by adding bits derived from a data packet, or string of bits, to the packet. The
CRC value is used at the receiving end to evaluate the data packet integrity,
and if it is not, the receiver will request a retransmission.
Decibel (dB)—
A measure of the ratio between two signal levels. Frequently
used to express the gain (or loss) of a system.
Data Circuit-terminating Equipment—
See DCE.
Data Communications Equipment—
See DCE.
Data Packet
—A group of data bytes of various lengths to be sent over-the
air. Each packet contains a header (preamble) followed by the data bytes.
Packet size will depend on network protocol and/or
Data Terminal Equipment—
See DTE.
dBi—
Decibels referenced to an “ideal” isotropic radiator in free space.
Frequently used to express antenna gain.
dBm—
Decibels referenced to one milliwatt. An absolute unit used to
measure signal power, as in transmitter power output, or received signal
strength.
DCE—
Data Circuit-terminating Equipment (or Data Communications
Equipment). In data communications terminology, this is the “modem” side
of a computer-to-modem connection. By default, GE MDS transceivers are
set as DCE devices.
Digital Signal Processing—
See DSP.
DSP—
Digital Signal Processing. DSP circuitry is responsible for the most
critical real-time tasks; primarily modulation, demodulation, and servicing of
the data port.
