Comtech EF Data CDM-570AL - Monitor: ACM

CDM-570A/570AL Satellite Modem with Optional Packet Processor
Revision 5
Front Panel Operation 6–49 MN-CDM570A
If the demodulator is locked, information displays as follows:
Parameter
Description
EbNo=
This shows the value of
E
b
/N
0
calculated by the demodulator. The value referred to here is the
energy per information bit (E
b
i), divided by the noise spectral density (N
0
).
SNR
This replaces “E
b
/N
0
” when VersaFEC ACM (IP-ACM) or VersaFEC-2 ACM (V2-ACM) mode is active.
In ACM, SNR is the preferred metric. Remember that:
SNR = Eb/No +10
log
(spectral efficiency)
.
BER=
This shows an estimate of the corrected BER.
∆F=
This shows the frequency offset of the received carrier, in kHz, in steps of 100 Hz.
Buf=
(Buffer fill state) This shows the fill state, in percent, of the receive Buffer. After a reset, it will read 50.
A value below 50 indicates that the buffer is emptying, and above 50 indicates that it is filling.
RSL=
(Receive Signal Level) This shows the value, in dBm, of the desired carrier’s input power as seen by
the demodulator. If the signal level is below the AGC range of the demod, this displays RSL <-99.
Otherwise, if the demodulator is not locked, the message ‘Demod: Not Locked’ displays, but
the screen continues to display the receive signal level, as this example shows:
Demod: Not Locked
RSL=-64
Press ENTER or CLEAR to return to the previous menu.
6.3.3.3 Monitor: ACM
This screen is viewable only when the optional Packet Processor is installed.
TMC00 BP.489 RmSNR=99.9
RMC00 BP.489 LcSNR=99.9
This read-only screen displays the active VersaFEC ACM (IP-ACM) or VersaFEC-2 ACM
(V2-ACM) mode information, as follows:
Setting
Function
TxModCod
Displays the Tx ModCod: 00-11 (VersaFEC); 00-35 (VersaFEC 2 Short Block (VF2S)); 00-37
(VersaFEC-2 Long Block (VF2L)).
RemoteSNR
Displays the SNR reported by the remote modem.
RxModCod
Displays the Rx ModCod: 00-11 (VersaFEC); 00-35 (VersaFEC 2 Short Block (VF2S)); 00-37
(VersaFEC-2 Long Block (VF2L)).
LocalSNR
Displays the SNR of the local unit.
When you attempt to access this display when the modem is not in VersaFEC ACM (IP-ACM) or
VersaFEC-2 ACM (V2-ACM) mode, the following message appears:
ACM Parameter is not avail