Comtech EF Data CDM-625A, Installation And Operation Manual

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CDM-625A Advanced Satellite Modem MN-CDM625A
Front Panel Operation Revision 4
6–84
Stats 116: 22.0,22.0,37,37,21.9,21,6
17/11/14 11:18:44 Clear-All: No (N/Y)
The modem calculates and then displays, on the top line from left to right, statistics data as
follows:
•
(22.0,22.0) First, the SNR is calculated: The
minimum
SNR value observed in the
measurement interval is provided first, and then the
average
SNR observed value follows.
The screen dislays 16.0 only if the measured values are ≥ 16.0 dB.
• (37) Maximum Rx ModCod, in decimal format, during the measurement interval.
•
(37) Minimum Rx ModCod, in decimal format, during the measurement interval.
•
( 22.6, 22.4) (21.6,21.6) Finally, the Receive Signal Level (RSL) is calculated (note that both
values are negative): The
minimum
value observed in the measurement interval is provided
first, and then the
average
RSL observed value follows.
6.2.3.5 Monitor: Rx Parameters
Rx-Parameters: EbNo=11.4dB ∆ F=+011.7kHz
BER=0.0E-9 Buffer=51% RxLevel=-43.5dBm
When in IP-ACM or V2-ACM mode:
Rx-Parameters: SNR=11.4dB
∆
F=+011.7kHz
BER=0.0E-9 Buffer=51% RxLevel=-43.5dBm
If the demodulator is locked, then this screen displays the following:
Item Description
Eb/No
This shows the value of Eb/No calculated by the demodulator. The value referred to here is the
energy per information bit (Ebi), divided by the noise spectral density (No).
SNR
(This item replaces “Eb/No” when IP-ACM or V2-ACM mode is active) In ACM, SNR is the preferred
metric. Remember that
SNR = Eb/No + 10
log
(spectral efficiency)
∆
F The frequency offset of the received carrier, in kHz, in increments of 100 Hz.
BER This is an estimate of the corrected BER.
Buffer
(Buffer fill state) This shows the fill state (in percent), of the receive Buffer. After a reset, it will read
50. A value <50% indicates that the buffer is emptying, and >50% indicates that it is filling.
Rx-Level A dBm reading indicating the signal level of the desired receive carrier in increments of 0.5 dB