Tektronix MTD200, Руководство пользователя

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Glossary
MTD200 MPEG Test Decoder User Manual
Glossary–7
Program Map Table (PMT)
The PMT is a PSI table. The elementary streams (vision, sound, data)
belonging to the individual programs are described in a PMT. A PMT
consists of one or several sections each containing information about a
program. The PMT is transmitted in TS packets with a PID from 0x0020 to
0x1FFE (referenced in the PAT) and indicated in table_ID 0x02.
Program Stream (PS)
Like the transport stream, the program stream is a multiplex stream but can
only contain elementary streams for a program and is only suitable for the
transmission in ‘undisturbed’ channels (eg recording in storage media).
Program Specific Information (PSI)
The four tables below defined by MPEG2 are summed up as program
specific information:
Program Association Table (PAT),
Program Map Table (PMT),
Conditional Access Table (CAT),
Network Information Table (NIT).
Quadrature Amplitude Modulation (QAM)
QAM is the modulation method used for transmitting a transport stream via
cable. The channel coding is performed prior to QAM.
Quadrature Phase Shift Keying (QPSK)
QPSK is the modulation method used for transmitting a transport stream via
satellite. The channel coding is performed prior to QPSK.
Source Coding
The aim of source coding is data reduction by eliminating redundancy to the
greatest possible extent and by affecting the relevance in a video or audio
signal as little as possible. The methods to be applied are defined in MPEG2.
They are the precondition that the bandwidth required for the transmission of
digital signals is narrower than that for the transmission of analog signals.
Running Status Table (RST)
The RST is an SI table and contains status information about the individual
broadcasts. It is transmitted in TS packets with PID 0x0013 and indicated by
table_ID 0x71.
Section
Each table (PSI and SI) may comprise one or several sections. A section may
have a length of up to 1 Kbyte (for EIT and ST up to 4 Kbytes). For most of
the tables, 4 bytes at the end of each section are available for the CRC.
Service Description Table (SDT)
The SDT is an SI table and contains the names of programs and broadcasters.
It is transmitted in TS packets with PID 0x0011 and indicated by table_ID
0x42 or 0x46.