SN User's Guide - ESC Home - NASA

NOTE:
Customers who operate in a SS-BPSK mode for one service
cannot reconfigure any of their Forward Services (i.e., MAF,
SMAF, SSAF, KuSAF, or KaSAF) to an SS-UQPSK mode.
Contact Code 450 if additional flexibility is required.
b. BPSK Modulation (PN Modulation Disabled). For data rates greater than 300
kbps, there is no PN code modulation and the customer data directly BPSK
modulates the carrier by +/2 radians.
NOTE:
The SN is capable of supporting non-spread BPSK signals
at data rates less than 300 kbps; however, its use will be
controlled and must be coordinated with GSFC Code 450.
c. Asynchronous Data Modulation. The forward service data will be asynchronous
with the carrier.
NOTE:
When the command channel does not contain any actual
forward service data, the forward service command channel
signal is carrier only.
d. Functional Configurations. A further description of the functional configurations
and data polarity ambiguity is found in Appendix B, paragraph B.2.2.
e. Doppler Compensation. The TDRSS KaSA forward service carrier frequency
(F) transmitted by a TDRS can optionally be compensated by the SN ground
terminal for Doppler. When compensated, the carrier, FR , arrives at the
customer platform receiving system within a predictable tolerance (E) of fo as
defined in Table 8-1. This feature minimizes the Doppler resolution
requirements of the customer platform receiver and is available continuously to
facilitate reacquisition by the customer platform in the event of loss of lock of
the TDRSS KaSA forward service signal. Doppler compensation may be
inhibited and the TDRSS will transmit a fixed-frequency KaSA forward service
carrier.
8.2.3 Communications Services
The TDRSS KaSA forward services available are listed in Table 8-2. Table 8-3 lists
their salient characteristics. The definitions for the parameters listed in Table 8-3 are
contained in Appendix E.
Revision 10 8-8 450-SNUG