Advantech SBD75e Series Installation And Operation Manual page 96

Term
Spectral Scrambling
TCP / IP
TS
TX
U
Upconverter
Uplink
UPS
UTC
SBD75e Series Demodulator Installation and Operation Manual
Description
A process (in digital transmission) used to combine a digital signal with a
pseudo-random sequence, producing a randomised digital signal that
conveys the original information in a form optimised for a broadcast
channel.
Transmission Control Protocol/Internet Protocol: A set of communications
protocols used to connect different computers over networks (in
particular the internet). TCP/IP consists of four layers: from lowest to
highest, these are the Link Layer, the Internet Layer, the Transport Layer,
and the Application Layer.
Transport Stream. A multiplex of video, audio and data (elementary)
streams combined (packetized) into a single synchronous transmission bit
stream. It is defined by the MPEG-2 compression and multiplexing
standard for the transmission of digital broadcast streams over satellite
links, terrestrial networks, and cable networks. These Packetised
Elementary Streams (PES) and System Information (SI) streams may
comprise more than one programme, but with common synchronisation
and error protection. The data structure is defined in ISO/IEC 13818-1 [1]
and is the basis of the ETSI Digital Video Broadcasting (DVB) standards.
Transmit or Transmitter.
44.45 mm (rack height standard).
A unit containing the electronic circuitry necessary to transform the
carrier frequency of a broadcast transport stream from a low
(intermediate) frequency to a high (radio) frequency - suitable for long-
distance transmission.
The part of the communications satellite circuit that extends from the
Earth to the satellite.
Uninterruptable Power Supply: A method of supplying backup power
when the electrical power fails or drops to an unacceptable voltage
level. Small UPS systems provide battery power for a few minutes; enough
to power down the computer in an orderly manner. This is particularly
important where write back cache is used.
Write back cache is where modified data intended for the disk is
temporarily stored in RAM and can be lost in the event of a power
failure. Sophisticated systems are tied to electrical generators that can
provide power for days. UPS systems typically provide surge suppression
and may provide voltage regulation.
Universal Time Co-ordinate: An internationally agreed basis for
timekeeping introduced in 1972 and based on international atomic time
(corresponds to Greenwich Mean Time or GMT).
Glossary
B-11