Tektronix MTD200, Руководство пользователя

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Measurement Functions
MTD200 MPEG Test Decoder User Manual
2–15
PTS_error (2nd priority)
Presentation Time Stamps (PTS values) in the PES headers are transmitted by
transport stream packets of a program. They enable the MPEG-2 decoder to
identify the exact time when a transmitted data block (TV picture for video
streams and beginning of an audio sequence for audio streams) is to be pres-
ented. The time stamps are transmitted with a word width of 33 bits and relate to
the 27 MHz system timing sequence transmitted in the transport stream together
with the PCR values.
In the DVB Measurement Guidelines (ETR 290), the preconditions for a
PTS_Error message are set as follows:
PTS ERROR is signaled if
magnitude of the difference of two consecutive PTS values following one another is > 700
ms
The above mentioned interval is given in the DVB Measurement Guidelines
(ETR 290) and is preset in the MPEG test decoder, but it can also be modified
according to individual requirements in the MONITORING / LIMITS menu
(refer to MONITORING / LIMITS Menu on page 4–15).
An error of this type is indicated in a cumulative message signaling several
single errors by the LED labeled OTHER lighting (line of LEDs at front panel).
As additional information, the PID of the program containing the faulty PTS
values can be obtained from the monitoring report.