1 (monitor: live alarms) unit, 2 monitor: rx-params – Comtech EF Data CDM-570 User Manual

Page 121

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CDM-570/570L Satellite Modem with Optional IP Module

Revision 12

Front Panel Operation

MN/CDM570L.IOM

5–35

5.2.2.2.1.1 (MONITOR: Live Alarms) Unit

Unit Fault: -12 Volt PSU
is Under-Voltage (ENT)


This screen indicates if there are any Unit Faults. If not, it displays ‘

None

’. Press ENTER to

return to the previous menu.

5.2.2.2.1.2 (MONITOR: Live Alarms) Receive (Receive Traffic Status)

Rx Traffic: AGC Alarm -

Reduce Input level (ENT)


This screen indicates if there are any Receive Traffic Faults. If not, it displays ‘

None

’. Press

ENTER to return to the previous menu.

5.2.2.2.1.3 (MONITOR: Live Alarms) Transmit (Transmit Traffic Status)

Tx Traffic: No Tx Clock
from Terrestrial (ENT)


This screen indicates if there are any Transmit Traffic Faults. If not, it displays ‘

None

’. Press

ENTER to return to the previous menu.

5.2.2.2.2

MONITOR: Rx-Params

EbNo>16.0dB BER=0.0E-9
ΔF
ט0.0k Buf=50 RSL=-42


If the demodulator is locked, information displays as shown here.

Note the following:

Item

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

).

BER=

This is an estimate of the corrected BER.

∆F=

The frequency offset of the received carrier, in kHz, with a displayed resolution 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 <50 indicates that the buffer is emptying, and >50 indicates that it is filling.

RSL=

(Receive Signal Level) A value in dBm, indicating the input power of the desired carrier, as seen by

the demodulator. If the signal level is below the AGC range of the demod, this will display RSL <-99.


Otherwise, if the demodulator is not locked, the message ‘Demod: Not Locked’ appears, but the
screen continues to display the receive signal level, as per the example that follows.

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