Table of Contents
Advertisement
Step
In all case except MEO (which is a very
unusual mode) the mode is fixed at
Normal. Enter the maximum permitted
power increase, between 0.0 and 9.9 dB.
You can choose to generate an alarm
when the max power or min ModCod has
been reached, or not at all. You can also
choose what happens to Tx Power when
the remote demod unlocks. The choices
are Nominal Power, Max Power, or Hold.
5
(SELECT) CONFIG: RX SYMB
Enter the desired receive symbol rate.
Note that asymmetric operation is
supported – transmit and receive symbol
rates do not have to be equal.
6
(SELECT) CONFIG: ACM
Configure the desired ACM operating
parameters, by selecting the ACM
submenu from the CONFIG: menu
branch.
Proceeding from the CONFIG: ACM
submenu:
Min/Max-ModCod: Define the range of
ModCods over which the system will
operate. ModCod0 is BPSK Rate 0.488
(0.49 bps/Hz), while ModCod11 is 16-
QAM Rate 0.853 (3.41 bps/Hz).
Unlock-Action: Choose the desired
action when the remote demod loses lock.
This is important, as the ACM system
depends on the feedback of the SNR
metric from the remote demod to
determine the optimum ModCod. The
choices are:
Go to min Tx ModCod (recommended)
–or– Maintain Tx ModCod
Appendix K
Task
If you wish to constrain the system to run at a fixed ModCod, set the Min and Max ModCod values
to be equal.
CAUTION – The value of Max ModCod may be limited by other FAST codes installed. For example,
suppose the 4100 ksps FAST option is installed, and the symbol rate set to 4100 ksps, the theoretical
maximum data rate would be 14 Mbps at ModCod 11. However, is CnC is being used, with a 10 Mbps
FAST limit, the ACM Max ModCod will be limited to ModCod 7, or 9.6 Mbps.
CDM-425 Advanced Satellite Modem
Front Panel VFD Mnemonic
AUPC-ACM Mode = Normal (Normal, +/- Track)
Max Permitted Power Increase: 3.0 dB ()
Tx Alarm: None (MaxPwr, MinMCod, None)
Rem Dmod Unlock Act=Nom Pwr(Nom, Max, Hold)
RxIF Freq FEC Demod Symb Descram Eq EbNo
(Data 02048.000kbps,02184.533ksps)()
RxSymbolRate = 01000.000 ksps (ACM Mode)
Data Invert=Off Clock Invert=Off
CONFIG: All
Mode Tx
CnC
EDMAC
Misc Mask
ACM Config: Min/Max-ModCod
Target-EbNo-Margin
Min Modcod: 00 (B
Max Modcod: 00 (B
When distant-end demod loses lock:
Go to min Tx ModCod (Maintain,Min)
K–13
Revision 0
()
Rx
Clocks
ACM
IP ()
Remote
Unlock-Action
()
0.488 0.488 bps/Hz)
0.488 0.488 bps/Hz)
()
MN-CDM-425
Advertisement
Table of Contents
