02.04.2013 Views

SN User's Guide - ESC Home - NASA

SN User's Guide - ESC Home - NASA

SN User's Guide - ESC Home - NASA

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Revision 10 C-12 450-<strong>SN</strong>UG<br />

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

Event Time<br />

PN code (DG1<br />

only) and carrier<br />

acquired<br />

Symbol and Viterbi<br />

decoder<br />

Synchronizers<br />

acquired; return<br />

service(s)<br />

established<br />

Equipment Status<br />

Customer Platform TDRS/Ground Terminal<br />

T5 = R + acq Continuing as above PN code despreader and<br />

carrier acquired; symbol<br />

synchronizer and Viterbi<br />

decoder processes start<br />

T7 = T5 + syn Continuing as above Symbol and Viterbi<br />

decoder, and deinterleaver<br />

synchronizers (if<br />

applicable) locked<br />

Remarks<br />

For coherent service, acq 1<br />

sec<br />

For noncoherent service, acq <br />

1 sec if customer platform<br />

transmitter frequency<br />

uncertainty is ± 700 Hz (Sband),<br />

± 5 kHz (Ku-band), ± 6<br />

kHz (Ka-band) and acq 3 sec<br />

if customer platform<br />

transmitter frequency<br />

uncertainty is ± 3 kHz (Sband),<br />

± 35 kHz (S-band), ± 20<br />

kHz (Ku-band), ± 21 kHz (Kaband)<br />

syn (seconds) 1100 /<br />

(channel data rate in bps) for<br />

biphase symbols (S-band DG2<br />

only);<br />

syn (seconds) 6500 /<br />

(channel data rate in bps) for<br />

NRZ symbols;<br />

For dual data channels,<br />

symbol and decoder<br />

synchronization must be<br />

achieved on each channel<br />

For DG2 services requiring<br />

channel ambiguity resolution<br />

by the ground terminal,<br />

additional time is required for<br />

the ground terminal to resolve<br />

the ambiguity.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!