Glossary
Transport Stream
A set of packetized elementary data streams and SI streams, which
may comprise more than one programme, but with common
synchronization and error protection. The data structure is defined in
ISO/IEC 13818-1 [1] and is the basis of the ETSI Digital Video
Broadcasting standards.
Transport Stream
Packet Header
A data structure used to convey information about the transport
stream payload.
TS
Transport Stream.
TSDT
Transport Stream Descriptor Table: A component of the MPEG-2
PSI data. This table describes which type of Transport stream it is in
(i.e. DVB, ATSC etc.). It may also contain other descriptors.
TSP
Transport Stream Processor.
U
44.45 mm (rack height standard).
UART
Universal Asynchronous Receiver Transmitter: A device providing a
serial interface for transmitting and receiving data.
UDP
User Datagram Protocol. A protocol above the IP layer that provides
port multiplexing in addition. In essence, you can transmit IP data
packets to several receiving processes in the same unit/device.
Unicast
Point-to-point connection, i.e. the "opposite" of multicast which is
one to many (or many to many). In this mode, a transmit unit sends
video data direct to a unique destination address.
Upconvert
The process by which the frequency of a broadcast transport stream
is shifted to a higher frequency range.
Uplink
The part of the communications satellite circuit that extends from the
Earth to the satellite.
UPS
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.
UTC
Universal Time Coordinated: The Coordinated Universal Time and is
synonymous with Greenwich Mean Time (GMT).
VCM
Video Compression Module.
VITC
Vertical Interval Time Code.
VITS
Vertical Interval Test Signal: See: ITS.
VLAN
Virtual LAN, a network of units that behave as if they are connected
to the same wire even though they may actually be physically
located on different segments of a LAN.
VPS
Video Programming System: A German precursor to PDC
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