Config: Clocks - Comtech EF Data CDM-600 Operating Instructions Manual

CDM-600 Satellite Modem
Front Panel Operation
CONFIG: RX: EbNo
RECEIVE EbNo ALARM POINT = 02.0 dB
Select the digit of the Alarm point to be edited using the [←] [→] arrow keys. Edit the
value of the digit using the [↑] [↓] arrow keys. Press ENTER.
The range of values is from 00.1 to 16.0 dB. The user may select a value here, and if the
Eb/No falls below this value, a receive traffic fault will be generated.
6.3.1.5

CONFIG: CLOCKS

CLOCKING:
EXT-BASEBAND-CLK
The sub-branches available are
CONFIG: CLOCKS: TX CLOCK
TRANSMIT CLOCK = INTERNAL(SCT)
(INT(SCT),TX-TERR(TT),RX-LOOP,EXT-CLK)
Use the [↑] [↓] arrow keys to select from the choices shown in parentheses, then press
ENTER.
INTERNAL (SCT)
TX-TERRESTRIAL
(TT)
RX-LOOP
EXTERNAL CLOCK
TX-CLOCK RX-BUFFER/CLOCK
EXT-FREQ-REF
:
Indicates that the unit will supply a clock to the DTE, which is derived from its
internal high-stability source. This is the required setting when the TX interface type
is Audio.
Indicates that the unit expects to receive a clock from the DTE, to which the unit
can phase-lock its internal circuits. If no clock is detected the modem will substitute
its internal clock and generate an alarm. This is the required setting when the
modem's interface type is G.703.
Will allow the modem's internal clock to be phase locked to the RX buffer clock
source. This output clock is Send Timing. Choosing RX-LOOP will not automatically
select RX-SAT as the buffer clock source. This allows for increased flexibility for
modem clock selection. Normally the user will select RX-SAT but the other choices
also are available.
Example: The user has an available high stability 10 MHz clock source but the end
equipment will only accept a clock at the information data rate. Selecting TX Clock
= RX-LOOP and RX buffer clock as EXT-REF will provide receive timing and send
timing to the end equipment that is sourced from the 10 MHz reference.
Indicates that an unbalanced high-stability source is expected at the J9 BNC
connector, or a balanced version at the P3A connector. The frequency must match
that programmed in the CONFIG: CLOCKS, EXTERNAL-BASEBAND-CLOCK
menu, and must be equal to the TX data rate.
6–19
MN/CDM600.IOM
INT-REF
Revision 7