Comtech EF Data CDM-600/600L - Manual (Page 262)

CDM-600/600L Open Network Satellite Modem Revision 3
Appendix G MN/CDM600L.IOM
G–4
G.3 BUC Power Class
Includes all power levels for C- and Ku-Bands.
Value Power
0x1 2 watt
0x2 4 watt
0x3 5 watt
0x4 8 watt
0x5 10 watt
0x6 16 watt
0x7 20 watt
0x8 25 watt
0x9 40 watt
0xa 60 watt
G.4 BUC Output Power Leveling
The BUC’s capability to report the detected high power BUC output carrier level via the FSK link
with the modem makes possible an automatic BUC output power leveling scheme. In this
scheme, the CDM-600L M&C continually monitors the reported output power level from the
BUC, and adjusts the modem transmit output carrier level to maintain the BUC output level at a
target tracking value.
This process is enabled when the FSK LEVELING is turned ON. When LEVELING changes
from OFF to ON, the CDM-600L M&C reads the output power level reported by the BUC, and
establishes that current output level as the target tracking level. Then, the M&C continues to
monitor the BUC output level at 10-second intervals, and adjusts the modem output carrier level
if needed to keep the BUC output level at the established target value.
With LEVELING turned ON, the BUC output power level is held constant within the stability of
the BUC output power detector.
BUC output power leveling cannot be used in conjunction with AUPC since the two processes
conflict directly with each other. Therefore, BUC output power leveling cannot be turned ON if
AUPC is ON, and vice versa. Further, BUC output power leveling cannot be turned ON if the
BUC output is turned off by the FSK command, or if the BUC PLL is faulted. In these cases,
there is no carrier output from the BUC so a valid tracking level cannot be established.
Once leveling loop operation is established, however, the loop will “freeze” if :
• A PLL fault in the BUC causes an automatic shut down of the output power amplifier.
• FSK communication fails.
• FSK is turned OFF.
• Modem IF output is turned OFF.
• FSK command turns OFF the BUC output.