Page 459 - Satellite Communications, Fourth Edition
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Satellite Access 439
Transmit terrestrial
interface modules
(TIM's)
Figure 14.12 Some of the basic equipment blocks in a TDMA system.
(these functions are described further in Sec. 14.7.4). In the INTELSAT
international network, at least two reference stations are used, one in the
East and one in the West. These are designated primary reference sta-
tions, one of which is further selected as the master primary. Each pri-
mary station is duplicated by a secondary reference station, making four
reference stations in all. The fact that all the reference stations are iden-
tical means that any one can become the master primary. All the system
timing is derived from the high-stability clock in the master primary,
