Comtech EF Data SDM-300A - Manual (Page 117)

SDM-300A Satellite Modem Revision 6
Front Panel Operation MN/SDM300A.IOM
5–23
FUNCTION SELECT: CONFIGURATION: INTERFACE:
TX CLOCK PHASE
TX CLOCK PHASE
AUTO
Transmit Clock Phase: AUTO, NORMAL, or INVERT
Note: AUTO is the default.
Upon entry, the current setting of the TX clock phase is displayed. Press [
↑] or [↓] to make the
selection. When AUTO is selected, the modem will automatically select NORMAL or INVERT
to properly phase the TX clock with the TX data. Press [ENTER] to execute the change.
FUNCTION SELECT: CONFIGURATION: INTERFACE:EXT-CLK FREQ
EXT-CLK FREQ
1544.000 KHz
Programs the EXT REF clock input frequency between 8.000 to 10000.000 kHz.
Note: The clock rate shall be equal to the data rate unless the asymmetrical loop timing option
is present.
This clock frequency can be any multiple of 600 Hz from 2.4 to 64 kHz, and can be any
multiple of 8 kHz from 64 kHz to 4.376 MHz. This can be used for the Doppler/plesiochronous
buffer clock. It can be a referenced to SCT. Use the master clock input on J8 for the external
master clock . The external reference on CP3 only allows for 1, 5, 10, and 20 MHz external
reference input.
Upon entry, the current setting for the external clock is displayed. Press [
←] or [→] to increase
or decrease the digit at the flashing cursor. Press [ENTER] to execute the change.