Modulator On/Off, Level; Channel / Frequency - Triax CGS-2 764 C Assembly Instructions Manual

Head-end digital modulator 4 x qam
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m
o d u l ato r
This menu item is used to set the output levels of the modulators of the modul´s
channel strips to the same value and to level them to the output levels of the
modulators of other modules used and to switch the modulators on or off.
Level setting:
• Measure and note down the output level of all modulators (of the whole
head-end station).
• By pressing
modulator with the lowest output level incrementally.
Switching the modulator on or off:
• Use the
• Use the
• Press the
C
h a n n e l
In this menu you can adjust the output channel (only at modulator A and C) or
the output frequency of the respective modulator.
/
, l
o n
o f f
e v e l
Bx 4A
on
adjust the higher output levels to the output level of the
button to place the cursor under "on" resp. "off".
buttons to switch each modulator on or off.
button.
—> The "Channel / Frequency" – "FREQ" submenu is activated.
/ f
r e Q u e n C y
—> The QAM signal is normally transmitted with a bandwidth of 8 MHz.
This means that you can only use the existing channel grid in the
range of channels C21...C69 (frequency grid 8 MHz).
The CCIR channel grid is 7 MHz in the range of the lower frequency
bands (channels C5 ... C12, S2...S20). If 8 MHz QAM signal
packages are transmitted in these channel ranges, this will result in
interference (overlapping) and transmission problems.
For programming in these channel ranges and in the frequency rang-
es below them, we recommend starting with frequency 306 MHz
going back in steps of 8 MHz (see frequency table on page 37).
Please note thereby that many receivers cannot receive the channel
ranges S21 ... S41 (306 ... 466 MHz).
LEVEL
– 3 dB
- 18 -
CGS-2 764 C

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