V2-Acm (Versafec-2 Acm) - Comtech EF Data CDM-570A Installation And Operation Manual

Use the ◄ ►arrow keys to select the Min(imum) (on the top line) or Max(imum) ModCod range
setting (on the bottom line). Then, use the ▲▼ arrow keys to define the range of ModCods (00-
11) over which the system will operate. Press ENTER.
ModCod 00 is BPSK Rate 0.488 (0.49 bps/Hz), while ModCod 11 is 16-QAM Rate 0.853
(3.41bps/Hz).
If you wish to constrain the system to run at a fixed ModCod, set the Min
and Max ModCod values to be equal.
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, if CnC is being used, with a 10 Mbps
FAST limit the ACM Max ModCod will be limited to ModCod 7, or 9.6 Mbps.
(CONFIG: TI) IP-ACM  Unlock-Action
Distant-end loses lock:
Go to Min Tx Modcod(▲ ▼)
Use this submenu to establish 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. Use the ▲▼ arrow keys to select Go to min Tx
ModCod (recommended) or Maintain Tx ModCod. Press ENTER.
(CONFIG: TI) IP-ACM  Target-SNR-Margin
Target SNR Margin:
1.0 dB (0.0 – 4.5)
Use the ▲▼ arrow keys to select a margin value from 0.0 to 4.5 dB, in 0.5 dB increments. Press
ENTER.
The ACM system is designed to switch based on thresholds that correspond to
a BER of 5 x 10
around two ModCods at this exact value, 0.3 dB of hysteresis has been added.
6.3.2.7.5

V2-ACM (VersaFEC-2 ACM)

This selection is functional only when the optional Packet Processor is installed.
ACM:ModCod Unlock-Action
Target-SNR-Margin
◄ ►
Use the arrow keys to select a parameter. Press ENTER.
Front Panel Operation
CDM-570A/570AL Satellite Modem with Optional Packet Processor
(▲ ▼)
-8
for each ModCod. However, in order to prevent oscillation
6–40
Revision 5
MN-CDM570A