Cisco Cisco D9887B HDTV Modular Receiver Guide De Montage

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Error Logic 
 
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11 
 
Error Logic 
Input Error Logic 
The input status is based on the selected input card’s status and the transport error 
indicator bit in the transport stream being decoded. For example, if the current input 
is VSB, the input status is based on: VSB receiver lock, RF channel level, and the 
MER level. The RF channel and MER thresholds can be set by the user. If the unit 
detects the presence of the transport error bit in a transport packet header, the input 
status will be an error for 0.5 seconds each time the TS error bit is set. The system 
must detect a constant cadence of sync bytes (0x47h) every 188 bytes and detect a 
valid PAT at least every 500 ms in order for the INPUT LED to illuminate. 
 
Decoder Error Logic 
The decoder error indicator is based on the decoder’s ability to decode what the user 
has requested. The input status will be alarmed differently depending on the current 
decoding mode: 
 
In "Auto Mode," the decoder status will be good unless the Video or Audio 
decoders cannot decode a stream. For example: a stream defines program 4 to 
have video on PID 52. If PID 52 is not actually present in the stream, or is un-
decodable, the decoder status will be in the error state. This is true for all modes. 
 
In "PID Lock Mode," the decoder status will be good if all of the PIDs entered by 
the user, for video and audio, are being decoded by the unit. If the user wants 
nothing to be decoded, the PID should be set to 0. If the user enters a PID which 
is not present or cannot be decoded, the decoder status will be in the error state. 
 
In "Program Priority Mode," the decoder status will be good if any priority is 
currently active and the Audio and Video represented by that priority are being 
decoded. If the PMT for a selected program lists a video or audio PID, but the 
decoder cannot decode that PID, the indicator will be in the error state. If the 
user enters an index for a priority that does not exist in the PMT, the indicator 
will still be good because the decoder will be set to decode nothing on that audio 
output. 
 
Temperature Error Logic 
The temperature error indicator is based on the correct operation of the unit. If the 
unit’s internal temperature exceeds 70 °C, the temperature status will be in the error 
state.