Figure 4-7. User Provides Data Only - Comtech EF Data SLM-7650 Installation And Operation Manual

SLM-7650 Satellite Modem
Theory of Operation
4.4.3.3.2.6 Timing Configuration #6: User Provides Data Only
Modem Reference clock is either INT 1, 5, 10, or 20 MHz
TX Clock Source = Data Source Sync
(X.21 operation will not have a TX terrestrial clock to the modem.)
Buffer clock is set to RX satellite (OFF or Bypass)
This user is generating the transmit clock from the send data (SD) (Figure 4-7).
The User must not use ST to generate SD.
User
generates SD
from a timing
source other
than ST
RT clocks
in the RD
Clock
Master
User
ST
SD
Clock
Recovery
RT
Modem

Figure 4-7. User Provides Data Only

4–30
Internal
clock
TRANSMIT
Receive
Buffer
Modem
Revision 4
MN/SLM7650.IOM
1, 5, 10,
or 20 MHz
Reference
detect
To TX IF Output
From decoder
User