GSS HDM 500 C, Руководство по сборке

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5 Programming
5.1 Preparation
• Connect the test receiver to the HF output or the test output of the head-end
station.
• Set the output channel / output frequency of the cassette (page 14 / 15) and
adjust the TV test receiver to this channel / frequency.
• Switch on the channel strip (modulator) if necessary (s. page 15). For each
channel strip, there is a status LED which indicates if the channel strip is
switched on.
• Balance the output levels of the channel strips “ A ” and “ B ” if the difference in
level is
≥
1 dB (page 15).
5.2 Notes on level setting
In order to prevent interference within the head-end station and the cable sys-
tem, the output level of the QPSK-QAM module must be lowered by 10 dB
compared to analogue modulators at 64 QAM, and by 4 dB compared to
analogue modulators at 256 QAM.
• Measure the output levels of the other cassettes and tune them to a uniform
output level using the appropriate level controls or software dependent on the
head-end station used. Please regard the assembly instructions of the respec-
tive head-end station.
Status-LED
Channel strip
"B"
Status-LED
Channel strip
"A"