Comtech EF Data CDM-600/600L - Manual (Page 86)

CDM-600/600L Open Network Satellite Modem Revision 3
Front Panel Operation MN/CDM600L.IOM
5–10
Having this feature enabled does not affect the internal IF loopback feature.
Be aware, however, that if an external IF loopback is attempted (connecting an
external cable from the Tx IF output to the Rx IF input), then this will not work!
(The Tx carrier cannot turn on until the demod is locked, and the demod
cannot lock because the Tx output is off. The net result is that the demod will
not lock and the Tx carrier will not turn on. USE THE RTI FEATURE WITH
EXTREME CARE!)
Edit the Tx Frequency by selecting each digit to be edited using the [ ←][→] arrow keys, then
edit the value of the digit using the [ ↑][↓] arrow keys. When editing is complete, press [ENT].
For the CDM-600L: Note that the range is from 950-1950 MHz.
For the CDM-600: Note that the range is from 52-88 MHz, and 104-176 MHz. The resolution is
100Hz. For units manufactured after February 2005 that display CDM-600(E) on the opening
menu, the range of IF frequencies has been extended to 50-90 MHz, and 100-180 MHz.
To set the Tx spectrum inversion, set SPECTRUM INVERT to OFF or ON using the [ ↑] [↓]
arrow keys. Press [ENT] when done.
IMPORTANT
SPECTRUM INVERT should normally be in the OFF position. When in the
ON position, for all FEC types, except BPSK, the transmit spectrum is
inverted (which is the same as reversing the direction of phase rotation in
the modulator). In BPSK, the time-order of bits out of the FEC encoder is
reversed, to make the modem compatible with certain other manufacturer’s
modems.
5.4.3.2 CONFIG: TX Æ POWER
OUTPUT POWER: MODE = MANUAL (MANUAL,AUPC)
OUTPUT POWER LEVEL = –20.0 dBm
To configure the Tx Output Power (for CDM-600L only – if in Manual Mode and BUC Leveling is
Off), select the parameter to edit – the output power Mode or the power Level – using the
[
←][→] arrow keys.
Select the output power Mode – MANUAL or AUPC – by using the [ ↑][↓] arrow keys.
To edit the output power Level, move the cursor to a digit of the Tx Power Level using the [ ←][→]
arrow keys, then edit the value of that digit using the [ ↑][↓] arrow keys. Press [ENT] when done.
If the Tx framing is EDMAC, or D&I++, or ESC++ or D&I, the power mode of AUPC may be
selected (see Chapter 7. AUTOMATIC UPLINK POWER CONTROL (AUPC) for more
information about this feature).
For these framing types, if AUPC mode is selected, the bottom line appears as shown:
OUTPUT POWER: MODE = AUPC (MANUAL,AUPC)
TARGET-EbNo-RANGE ALARM/ACTION
Select TARGET-EbNo-RANGE or ALARM/ACTION using the [ ←][→] arrow keys, then
press [ENT].