Cisco Cisco Explorer Set-top Software Version 2.1 Guia Do Utilizador
Chapter 11 WatchTV Issues
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Digital Channels Freeze or Block (Macroblocking)
Description
The picture on a digital channel freezes, or shows blocking or tiling (macroblocking).
Possible Causes
Some type of interference with the external signal.
The signal-to-noise (S/N) ratio is out of range.
The signal level is not within the acceptable working range.
Diagnosing the Issue
See the following table to diagnose why a digital channel is freezing, showing
blocking, or showing tiling.
Important: Please check all of the diagnostic screens and fields contained in the
Important: Please check all of the diagnostic screens and fields contained in the
following table before you contact Cisco Services. Various combinations of failures
will point to the source of any potential problems as listed in the following
examples.
Examples:
Examples:
If the signal levels are good, the S/N value is poor, and there is a rapid change in
byte counts, then noise ingress is present.
If the signal levels are poor, the S/N value is poor, and there is a rapid change in
byte counts, then there is a "drop" problem.
If the signal levels, S/N value, and byte counts are good, and a problem
continues to exist, an issue exists prior to the QAM or transport network.