Comtech EF Data CDM-760 User Manual
Page 101
Front Panel Operation
Revision 2
CDM-760 Advanced High-Speed Trunking Modem
MN-CDM760
6–15
(CONFIG: Tx) Power Carrier
Use the arrow keys to select On or Off.
(CONFIG: Tx) Power Level
Use the arrow keys to select a digit, and then use the arrow keys to change that digit.
Press ENTER. Valid settings are:
Tx Frequency Range
Power Levels
50 to 180 MHz
0 to –25 dBm
950 to 2250 MHz (L-Band)
0 to –40 dBm
(CONFIG: Tx) Power PowerControl
Use the arrow keys to select Manual or AUPC. Press ENTER.
(CONFIG: Tx) Power PowerControl Manual
Select Manual to set the modem’s output power level to be the same as the Tx power
level value configured with (CONFIG: Tx)PowerLevel.
(CONFIG: Tx) Power PowerControl AUPC
Select AUPC to place the modem in AUPC (Automatic Uplink Power Control) Mode.
AUPC is a means to automatically adjust the Tx power of the modem based on user-
defined parameters and feedback from the far-end demodulator’s Es/No level. When
this option is purchased, AUPC directs the modem itself to take control of the output
power within the AUPC operating parameters configured with (CONFIG: Tx) Power
AUPC (see next).
(CONFIG: Tx) Power AUPC
AUPC: Target:06.0 dB LCL:Nom RCL:Nom
Nominal:-25.0 dBm Range:03.0 dBm
()
Use the arrow keys to select a parameter. Press ENTER.
Use this menu to define AUPC minimum and maximum operating boundaries. AUPC adjusts the
modulator’s power in order to match a desired Es/No level.
AUPC Compensation Rate: As with any closed-loop control system, the loop parameters must
be chosen to ensure stability at all times. Several features are incorporated to ensure that the
AUPC system does overshoot, or oscillate:
•
In Normal (GEO, or geosynchronous satellite) operating mode, the rate at which
corrections are made to the output power is fixed at 1X/second. This takes into account the
round trip delay over the satellite link, the time taken for a power change to be reflected in
the remote demodulator’s value of Eb/No, and other processing delays in the modems.