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Glossary
Bouquet A collection of services (TV, radio, and data, or any combination of
the three) grouped and sold together, and identified in the SI as a
group. A single service may be in several bouquets.
B-Picture; B-Frame Bi-directionally Predictive Coded Picture/Frame: A picture that is
coded using motion-compensated prediction from previous I or P
frames (forward prediction) and/or future I or P frames (backward
prediction). B frames are not used in any prediction.
BPSK
Binary Phase Shift Keying: A data modulation technique.
Buffer
A memory store used to provide a consistent rate of data flow.
BW Bandwidth: The transmission capacity of an electronic line such as
(among others) a communications network, computer bus, or
broadcast link. It is expressed in bits per second, bytes per second
or in Hertz (cycles per second). When expressed in Hertz, the
frequency may be a greater number than the actual bits per second,
because the bandwidth is the difference between the lowest and
highest frequencies transmitted. High bandwidth allows fast
transmission or high-volume transmission.
Byte-mode Each byte is delivered separately in the ASI transport stream, with
stuffing data added between the Bytes to increase the data rate to
270 Mbps. See DVB Document A010 rev. 1, Section B3.3, (ASI)
Layer-2 Transport Protocol.
CA Conditional Access: The technology used to control the access to
viewing services to authorized subscribers through the transmission
of encrypted signals and the programmable regulation of their
decryption by a system such as viewing cards.
CAT Conditional Access Table: Part of the MPEG-2 Program Specific
Information (PSI) data. Mandatory for MPEG-2 compliance if CA is
in use.
C-Band The portion of the electromagnetic spectrum, which spans the
frequency range of approximately 4 GHz to 6 GHz. Used by
communications satellites. Preferred in tropical climates because it
is not susceptible to fading.
CCIR
See: ITU-R.
CCITT
See: ITU-T.
Channel a narrow range of frequencies, part of a frequency band, for the
transmission of radio and television signals without interference from
other channels.
In the case of OFDM, a large number of carriers spaced apart at
precise frequencies are allocated to a channel.
Channel Coding A way of encoding data in a communications channel that adds
patterns of redundancy into the transmission path in order to
improve the error rate. Such methods are widely used in wireless
communications.
EN/LZT 790 0003/2 R1A
A-3