Comtech EF Data SDM-650B - Manual (Page 92)

Configuration SDM-650B Satellite Modem
3–50 Rev. 5
3.6 Interface Clocking Options
Clocking of the data from the terrestrial circuits to the satellite, and vice versa, will
depend upon the application. The most common options and recommended
configurations are described in the following sections.
3.6.1 Master/Slave
This application is used where the far end earth station does not have local access to a
high stability reference clock, or when it is not required to synchronize with a local clock.
The disadvantage of the master/slave application is that the signal received at the slave
station is subject to Doppler shift.
Note: The length of the buffer at the master end will need to be twice the length that is
normally required (since it will be compensating for the Doppler shift on the outward and
return paths).