Glossary
Glossary–2
MTD200 MPEG Test Decoder User Manual
Definition of Terms (Cont.)
Acronym
Definition
TDT
Time and Date Table
TOT
Time Offset Table
TS
Transport Stream
Adaptation Field
The adaptation field is an extension of the TS header and contains ancillary
data for a program. The program clock reference (PCR) is of special
importance. The adaptation field must never be scrambled when it is to be
transmitted (see Conditional Access).
Asynchronous Serial Interface (ASI)
The ASI is an interface for the transport stream. Each byte of the transport
stream is expanded to 10 bits (energy dispersal) and is transmitted with a
fixed bit clock of 270 MHz (asynchronous) irrespective of the data rate of
the transport stream. The fixed data rate is obtained by adding dummy data
without information content. Useful data is integrated into the serial data
stream either as individual bytes or as whole TS packets. This is necessary to
avoid PCR jitter. A variable buffer memory at the transmitter end is therefore
not permissible.
Bouquet Association Table (BAT)
The BAT is an SI table. It contains information about the different programs
(bouquet) of a broadcaster. It is transmitted in TS packets with PID 0x11 and
indicated by table_ID 0x4A.
Common Interface (CI)
The CI is an interface at the receiver end for a broadcaster–specific ex-
changeable CA plug–in card. This interface allows scrambled programs from
different broadcasters to be descrambled with the same hardware despite
differences in CA systems.
Conditional Access (CA)
The CA is a system allowing to scramble programs and to provide access to
these programs at the receiver end only to authorized users. Broadcasters can
thus charge fees for programs or individual broadcasts. Scrambling can be
performed at one of the two levels provided by an MPEG2 multiplex stream,
ie the transport stream or the packetized elementary stream level. The
relevant headers remain unscrambled. The PSI and SI tables also remain
unscrambled except for the EIT.
Conditional Access Table (CAT)
The CAT is a PSI table and comprises information required for descrambling
programs. It is transmitted in TS packets with PID 0x0002 and indicated by
table_ID 0x01.
Summary of Contents for MTD200
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Page 29: ...Introduction to Digital TV Transmission Technique 1 14 MTD200 MPEG Test Decoder User Manual...
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Page 167: ...Remote Control 5 70 MTD200 MPEG Test Decoder User Manual...
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Page 174: ...Maintenance and Checking 6 6 MTD200 MPEG Test Decoder User Manual...
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Page 204: ...Glossary Glossary 10 MTD200 MPEG Test Decoder User Manual...
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Page 209: ...Index Index 4 MTD200 MPEG Test Decoder User Manual...
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