ADInstruments S7200 Operation Manual page 201

AD INSTRUMENTS S7200 TV Signal Analyzer Operation Manual
(6) PID_error: The PIDs of all elementary streams of a given program are
contained in the associated program map table (PMT). The PIDs are pointers to
the elementary streams: they are used to access to the corresponding packets of
the elementary stream to be decoded. If a PID is listed in a PMT but not
contained in the transport stream, the decoder will be unable to access the
corresponding elementary stream.
A "PID_error" occurs when
• Transport stream packets with a PID referred to in a PMT but not contained in
the transport stream or
• Their repetition rate exceeds a user-definable limit which is usually 500 ms or
less.
Priority 2 parameters include: Transport_error, CRC_error, PCR_repetition_error,
PCR_discontinity_indicator_error, PCR_accuracy_error, PTS_error, CAT error.
(1) Transport_error
Every MPEG-2 transport stream packet contains a bit called Transport Error
Indicator which is transmitted right after the sync byte. This bit flags any errors in
the transport stream packets at the receiver. During the transmission, bit errors
may occur for various reasons. If error protection (at least Reed Solomon in DVB
and ATSC) is no longer able to repair all errors in a packet, this bit is set indicating
this packet can no longer be utilized by the MPEG-2 decoder and must be
discarded.
A transport_error (Fig. 11.5.) occurs when
• The transport error indicator bit in the TS header is set to 1.
(2) CRC_error
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