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HDMT 1290
2.5 Software query
Control unit
If necessary, you can activate the indication of the software version of the
control unit manually:
• Press any two keys on the control unit of the head-end station simultaneously
until the display goes dark and the software version, e.g. “
V 41
” appears.
2.6 How the TPS module works
After decoding COFDM-modulated signals, the demodulated data streams
can be accessed via the integrated TPS module. These data streams, also
called transport streams, contain several stations in all their components (vid
-
eo, audio, data and service information), which can be changed using the TPS
module.
Station filter
Individual stations can be deleted. This reduces the data rate and, conse
-
quently, the output symbol rate.
Stuffing
The transport stream is padded using what is known as zero data. This ensures
a steady and constant output data rate.
Changing the Transport stream and ORGNET-ID
The transport stream ID can be changed. If the stations of a transponder are
split into the transport streams of the channel strips ”A” and ”B”, one of the both
transport streams a new identification must be allocated to realise the channel
search of the settop boxes connected without mistakes.
If the ORGNET-ID is changed a new NIT must be generated.
Changing the NIT
The transport stream contains data in the form of tables which the receiv-
ers evaluate and require for convenient use. The TPS module can adjust the
“Network Information Table” (NIT) to accommodate the new station data. The
“NIT” contains data which is required by the set-top boxes connected to the
cable network for the automatic search feature.