Comtech EF Data CDM-425, Installation And Operation Manual

Page: 204 / 744

CDM-425 Advanced Satellite Modem
Revision 0
Front Panel Operation 6–86 MN-CDM-425
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 + 10log(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
6.2.3.6 Monitor: RemoteEbNo
The appearance of this screen varies depending on the active mode of operation.
For example, when a valid mode of operation is active:
Remote EbNo= Unlock
However, when an invalid mode of operation is active (e.g., Quad Drop & Insert):
Not applicable without EDMAC/EDMAC2/D&I/
D&I++/ESC++/FrmQDI/EDMAC3/VFEC-2/IP-ACM
6.2.3.7 Monitor: AUPC Parameters
The presentation of information varies slightly when in IP-ACM or V2-ACM mode.
For all modes except IP-ACM or V2-ACM:
AUPC-Params: Remote EbNo= 6.8 dB
Transmit Power Increase= 1.2 dB
The top line displays the value of Remote Eb/No of the demodulator at the distant end of the
satellite link. The Remote Eb/No displays
Unlock if the remote Demod is unlocked.
The bottom line shows how much the AUPC system has increased the output power. If AUPC is
not enabled, then the value of Tx Power Increase displays as 0.0 dB.