Scientific Atlanta Continuum DVP eXtra Dense QAM Array 24, Руководство по настройке

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Configuring the Quad Channel QAM Card
4018055 Rev B 31
Configuring the Quad Channel QAM Card
Introduction
Before starting the configuration of the Quad Channel QAM cards, the QAM
Encoding type (ITU-A, ITU-B or ITU-C) of the XDQA24 system must be set. The
procedure to set this parameter can be found in topic General Configuration Settings
on page 20.
Channel Center Frequencies and Channel Spacing
Only the center frequency of the lower channel needs to be defined.
As the upper channel is adjacent to the lower channel, its center frequency is
defined by the lower channel frequency and the channel spacing.
The minimum lower channel frequency is 45.000 MHz + 0.5 x Channel spacing.
The maximum lower channel frequency is 1000.000 MHz - 1.5 x Channel spacing.
The channel spacing for an ITU-B or ITU-C configured XDQA24 system is
predefined on 6 MHz. The channel spacing for an ITU-A configured XDQA24
system can be set to 7 or 8 MHz.
Notes:
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The lower channel center frequency of an ITU-B or ITU-C configured
XDQA24 system can be set between 48 and 991 MHz because the channel
spacing between the lower channel frequency and the upper channel
frequency is fixed (6 MHz).
-
If the lower channel center frequency is set to a value outside this range, a
message box is displayed .
-
When the QAM Encoding Type of the XDQA24 system is set to ITU-B, the
lower channel center frequency can be chosen by entering the corresponding
EIA digital channel number. The relation between the EIA digital channel
numbers and the channel center frequencies can be found in appendix EIA
Channel Numbers on page 75.
Both the lower channel center frequency and the spacing frequency can be
defined for each RF output.
Constellation Grade
The constellation grade can be set to QAM64 or to QAM256 for both RF outputs
of a Quad Channel QAM card together.