GSS HDMA 784 C ASI, Руководство по сборке

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- 13 - HDMA 784 C ASI
5 p
rogramming
5.1 p
repar ation
• Test the software versions of the head-end station and the QAM module and
update them if necessary. The current software versions can be found on the
website "
www.gss.de/en ".
• Connect the test receiver to the modulator output on the QAM module
D
or to
the HF output on the output collector if it is already connected (page 11).
• Adjust the test receiver to the output channel / output frequency of the chan-
nel strip to be set.
• Switch on the channel strip (modulator) if necessary (page 18). For each chan-
nel strip, there is an status LED which indicates if the channel strip is switched
on.
Status LEDs
Channel strip A
Channel strip B
Channel strip C
Channel strip D
• Balance the output levels of the channel strips " A " … " D " and level them to
the output levels of the modulators of other modules used if the difference in
level is
≥ 1 dB (page 18).
5.2 n
otes on level set ting
In order to prevent interference within the head-end station and the cable sys-
tem, the output level of the cassette must be decreased by 10 dB compared to
analogue cassettes at 64 QAM, and by 4 dB compared to analogue cassettes
at 256 QAM.