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Acquisition (note 3) (cont’d):
Table 5-8. TDRSS MA Return Service (cont’d)
Parameter (Note 7) Description (note 7)
Channel Symbol/Deinterleaver(PCI)/Decoder
Synchronization Acquisition (note 5):
Minimum data bit transition density > 64 randomly distributed data bit transitions
within any sequence of 512 data bits
Number of consecutive data bits without a
transition
Revision 10 5-25 450-SNUG
< 64
P rec (dBW) consistent with the Prec for BER
Acquisition time (in seconds) with >99%
probability:
Signal Tracking
Rate 1/2 coding Average: < 36000/(Channel Data Rate in bps)
Maximum: < 66000/(Channel Data Rate in bps)
Rate 1/3 coding Average: < 26000/(Channel Data Rate in bps)
Maximum: < 46000/(Channel Data Rate in bps)
Orbital dynamics During Free Flight refer to paragraph 5.3.3.3 a
Reacquisition (powered (SMAR only) and nonpowered
flight)
Duty factor 100 percent
During Powered Flight (SMAR only) refer to
paragraph 5.3.3.3.b
refer to paragraph 5.3.3.4
Notes:
1. The BER is for a customer platform transmitting a signal on an AWGN channel which complies with
the constraints defined in Table 5-11. Refer to Appendix G for a discussion of the additional
degradation potentially applicable to TDRSS MA return performance service due to S-band RFI.
2. The required customer Prec must meet the Prec for BER or signal acquisition, whichever is greater.
Paragraph 5.3.3.2.b provides the required Prec description for each possible MAR data
configuration. Refer to Appendix A, paragraph A.4, for a definition of Prec. The minimum required
Prec equations for BER produce the minimum Prec for a given data rate for all possible signal
characteristics. CLASS analysis will produce a more accurate performance projection based upon
desired customer signal characteristics, such as data rate, data type, and jitter values. The Prec
equations for BER include 2 dB for self and mutual interference degradation. Appendix O provides
an assessment of self and mutual interference in the TDRSS MA environment at 2287.5 MHz. The
amount of self and mutual interference included in a customer’s MAR/SMAR link budget should be
negotiated with GSFC Code 450. SN support may be possible for customers whose Prec is less
than the required Prec for 10 -5 BER performance; however, such support shall be coordinated
through GSFC Code 450. In general, customer platforms should be designed to the most limiting
TDRS to ensure SN support can be provided.