Interface Menu - Comtech EF Data SLM-7650 Installation And Operation Manual

SLM-7650 Satellite Modem
Operation
3.4.1.3

Interface Menu

Menu Item
TX CLOCK SOURCE
TX CLOCK PHASE
SCT PLL REF
Programs the clock source for the modem transmitter clock to the following
configurations:
TX Terrestrial: Selecting TX Terrestrial will clock the data to the encoder using the
customer terrestrial clock. Another term for this clock is terminal timing.
SCT (Internal): Setting SCT as the TX clock source will clock the data to the
encoder using the internal clock of the modem. This indication will
change to SCT (Loop) when loop timing is turned on.
Data Source Sync: The Clock for the modem input data will be recovered from the
transitions of the input data. This clock is then used to phase lock the
internal SCT clock and to clock the transmit data to the encoder. The
SCT PLL REF will display Data Source Sync and can only be changed by
selecting either SCT (Internal) or TX Terrestrial in this menu.
On entry, the current transmit clock setting is displayed. Press an arrow key to make
the selection. Press [ENTER] to execute the change.
Programs the TX clock phase to Normal or Invert.
On entry, the current setting of the TX clock phase is displayed. Press [↑] or [↓] to
make the selection. Press [ENTER] to execute the change.
Programs the timing source for the Serial Clock Transmit (SCT) Phase Lock Loop
(PLL).
MODEM REF Source (Uses the timing standard that is programmed in the Modem
Reference menu.)
EXT MASTER CLOCK (The MC input is on the baseband data interface. The
frequency must be programmed in the Ext Master Clock Frequency menu screen.)
DATA SOURCE SYNC (appears only when DATA is selected as the Tx Clock
source)
RX Loop (appears only when Loop Timing is ON)
De-selecting DATA or Rx Loop is accomplished at the CONFIG / INTERFACE
MENU
On entry, the current timing source is displayed. Press [
Press [ENTER] to execute the change.
3-12
Specifications/usage
↑ ] or [
Revision 4
MN/SLM7650.IOM
↓ ] to make the selection.