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SN User's Guide - ESC Home - NASA

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Revision 10 C-14 450-<strong>SN</strong>UG<br />

Table C-3. Acquisition Events for TDRSS Services (Normal Forward and Return) (cont’d)<br />

Event Time<br />

Forward service<br />

symbol<br />

synchronization<br />

achieved and frame<br />

synch word<br />

identified; forward<br />

service established;<br />

customer platform<br />

begins forward<br />

service data<br />

processing<br />

T10 = T9 + bit<br />

Equipment Status<br />

Customer Platform TDRS/Ground Terminal<br />

Symbol synchronizer locked<br />

and frame synch word<br />

recognized; command<br />

processing enabled<br />

Remarks<br />

Continuing as above bit is approximately 128 bit<br />

times (i.e., 128 bits after<br />

customer platform receives<br />

data modulated forward<br />

service signal<br />

Note:<br />

This can be achieved at the end of the previous forward service support period or by stored on-board commands. If coherent return<br />

service operations are scheduled later in this same service support period, the transponder can be set to permit automatic transition<br />

to coherent turnaround mode at, or prior to, the scheduled start of the coherent return service operations. This can also be<br />

achieved either via stored on-board commands or via commands imbedded in the forward service data once the forward service is<br />

established.

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