2.5 Software query
Control unit
If necessary, you can activate the indication of the software version of the con-
trol 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 37
” appears.
2.6 How the TPS module works
After decoding QPSK- or 8PSK-modulated signals, the demodulated data stream
can be accessed via the integrated TPS module. This data stream, also called
transport stream, contains several stations in all their components (video, audio,
data and service information), which can be changed using the TPS module.
The individual functions
Station filter
Individual stations can be deleted. This reduces the data rate and, consequently,
the output symbol rate required.
Stuffing
The transport stream is padded using what is known as zero data. This ensures
a steady and constant output symbol rate.
Changing the NIT
The transport stream contains data in the form of tables which the receivers
evaluate and require for convenient use. The TPS module can adjust the “Net-
work Information Table” (NIT) to accommodate the new station data. The “NIT”
contains data which is required by the set-top box for the automatic search
feature.
