AXING SKQ 2-01 - Manual (Page 13)

Programming
SKQ 2-01
© AXING AG – state of the art: July 2012 – Reserving change in design and type Page 13
4.7 Modulator
Fig. 22 Modulator
Select the menu item “Modulator” and confirm
with OK.
Fig. 23 Modulator menu
At the bottom of the modulator menu a bar
appears after approx. 5 seconds.
The bar shows the work load of the output
channel in percent. The work load depends on
the selected output channel (7 or 8MHz), the
DVB-C constellation settings (QAM 32 to QAM
256) and the number of previously selected
programs in the channel list.
Since the data rate changes permanently
depending on the content of the image, the
rate should not exceed 80%. Otherwise, image
interferences such as mosaic pictures may
appear.
If the displayed data rate exceeds 80%,
change to a 8 MHz channel (if a 7 MHz channel
was selected previously) or increase the
modulation rate. With QAM 256 the largest
amount of data can be transmitted. If this is not
enough, delete one or more programs from the
channel list, but this is not necessary with QAM
256.
4.7.1 Output channel (CCIR)
Set the desired output channel by means of the
VOL / VOL keys or the / keys.
All channels 5 to 12 and 21 to 69 and all special
channels S2 to S41 can be selected.
The channel number is displayed on the
module.
If a special channel is selected, a point is
displayed between the two digits on the
module display.
4.7.2 DVB-C Constellation
The settings QAM 32, QAM 64, QAM 128 and
QAM 256 can be selected by means of the
VOL / VOL keys.
Fig. 24 DVB-C Constellation
4.7.3 DVB-C symbol rate
Use the numerical keypad to enter the DVB-C
symbol rate from 1000 to 8000.
For channels using a bandwith of 8MHz, 6900
is the most common symbol rate in German
cable networks.
Channels S02-S10, 5-12 and S11-S20, having
a specified bandwith of 7 MHz, can not be
driven using the setting 6900 for adjacent
channels.
If even so adjacent channels shell be driven in
this area, the symbol rate must be reduced.
For example to 6111.
The DVB-C receiver used in the network must
be set to the same symbol rate and DVB-C
modulation as the SKQ 2-01.
4.7.4 Output level
Select the menu item “Output level” and
confirm with OK.
Set the output level of the modulator in steps of
1dB by means of VOL / VOL .
20 corresponds to 105 dBµV. The maximum
level decrease is -20dB (setting = 0).
4.7.5 Fine tune
If the output channel does not correspond to
the CCIR pattern, the output frequency can be
changed using the Fine Tune adjustment.
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02
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