Comtech EF Data CDM-740, Installation And Operation Manual

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CDM-740 Advanced Satellite Modem Revision 0
Front Panel Operation MN-CDM740
5–27
5.9 SELECT: ODU
The CDM-740 modem is able to interface with various ODUs (Outdoor Units). These are:
•
L-Band BUC (Block Upconverter);
•
L-Band LNB (Low Noise Block Downcoverter).
The ODU configuration menus allow the user to set up power supplies, a 10 MHz reference and
low/high current alarm thresholds for the BUC and LNB. LO menus for the BUC and LNB allow
the user to set up the up-convert and down-convert parameters for the BUC and LNB so that the
user can view the satellite frequencies as well as the modem IF input/output frequencies.
BUC: BUC_LO Power 10M-Ref Alarm Monitor
LNB: LNB_LO 22K-Tone Polarity
(
◄►
)
Use the
◄ ►
arrow and
ENTER
keys to select a submenu. Note the following:
For Submenu Permits user to…
BUC
(Top line)
BUC_LO … enter a BUC LO (local oscillator) frequency and (+/-) sign.
Power … set BUC power supply parameters.
10M-Ref
… control the BUC 10MHz Reference.
Alarm … control BUC high and low alarm limits.
Monitor … monitor BUC power supply and current parameters.
LNB
(Bottom line)
LNB_LO
… enter an LNB LO (local oscillator) frequency and (+/-) sign.
22K-Tone … set the 22KHz tone outbound from L-Band connector per DiSEq 4.2
Polarity
… control the LNB DC Power. Note the following:
•
OFF = DC Power is off
•
Horizontal is on 18V
•
Vertical is on 13V.
5.9.1 ODU: (BUC:) BUC_LO
BUC_LO: 00000.000 MHz
Terminal Mix: [+] TTF: +1950.0000
On the top line, the user may enter the BUC LO frequency for the up conversion. Entering a non-
zero value for BUC LO will cause the Tx-IF frequency menu to show LO and Satellite frequencies.
Edit the BUC LO frequency by using the
◄ ►
arrow keys to select the digit to be edited, then use
the
▲ ▼
arrow keys to set the value of that digit. The valid LO range is 3000 to 65000 MHz.
On the bottom line, the
Terminal Mix
sets the polarity for the upconversion mix in the BUC:
•
[+]
indicates a high side, inverting mix;
•
[–] indicates a low side, non-inverting mix.
Note: Satellite frequency = LO fre/- modem frequency .
To set the sign for the Terminal Mix, use the
◄ ►
arrow keys to navigate to the setting, then use
the
▲ ▼
arrow keys to edit the Terminal Mix setting as positive [+] or negative [–].
Note:
The
TTF:
(Transmit Terminal Frequency) value is provided on a ‘
status only
’ basis.