The secure voice subsystem is a narrowband UHF
link that enables secure voice communications between
ships. It also allows, connection with wide-area voice
networks ashore.
Tactical Intelligence (TACINTEL)
Subsystem
TACINTEL is specifically designed for special
intelligence communications.
Control Subsystem
The Control subsystem is a communications
network that facilitates status reporting and
management of FLTSATCOM system assets.
Officer in Tactical Command Information
Exchange Subsystem (OTCIXS)
OTCIXS is designed as a communications link for
battle group tactical operations.
Teleprinter Subsystem (ORESTES)
ORESTES is an expansion of the existing
teleprinter transmission network.
LEASAT TELEMETRY TRACKING AND
COMMAND SUBSYSTEM
The LEASAT Telemetry Tracking and Command
subsystem is a joint operation between the U.S. Navy
and contractors for controlling LEASATS. The
installation of subsystem baseband equipment and RF
terminals aboard ships and aircraft is determined by
communications traffic levels, types of
communications, and operational missions.
Since Fleet Satellite Broadcast message traffic is a
common denominator for naval communications, it is
received by numerous types of ships. In some
installations, such as large ships, the fleet broadcast
receiver represents one part of the FLTSATCOM
equipment suite. A typical configuration on a large ship
would include fleet broadcast, CUDIXS/NAVMACS,
secure voice, OTCIXS, TADIXS, teleprinter, and
TACINTEL equipment.
The FLTSATCOM subsystems apply some form of
automated control to the communications being
transmitted with the exception of the secure voice and
control subsystems. This includes message or data link
processing before and after transmittal and control of
the RF network (link control) in which the messages are
being transmitted. The automation of these functions is
handled by a processor.
Much of the message processing before
transmission and after receipt is fully automatic and
does not require operator intervention. The actual
message or data link transmission is fully automated
and under the control of a processor. Within the
limitations of equipment capability, each subsystem
addresses the unique requirements of the user and the
environment in which the user operates.
DEMAND ASSIGNED MULTIPLE ACCESS
(DAMA)
DAMA was developed to multiplex several
subsystems or users on one satellite channel. This
arrangement allows more satellite circuits to use each
UHF satellite channel.
Multiplexing
The number of communications networks being
used is constantly increasing. As a result, all areas of the
RF spectrum have become congested. Multiplexing is a
method of increasing the number of transmissions
taking place in the radio spectrum per unit of time.
Multiplexing involves the simultaneous
transmission of a number of intelligible signals using
only a single transmitting path. As we mentioned
earlier, the Navy uses two multiplexing methods: time-
division multiplexing (TDM) and frequency-division
multiplexing (FDM). We have already discussed FDM
with the AN/UCC-1. Additional information
concerning both methods can be found in Radio-
Frequency Communication Principles, NEETS,
Module 17.
A UHF DAMA subsystem, the TD-1271/U
Multiplexer, was developed to provide adequate
capacity for the Navy and other DOD users. This
subsystem was developed to multiplex (increase) the
number of subsystems, or users, on 1 25-kHz satellite
channel by a factor of 4.
This factor can be further increased by multiples of
4 by patching 2 or more TD-1271s together. This
method increases the number of satellite circuits per
channel on the UHF satellite communications system.
Without this system, each satellite communications
subsystem would require a separate satellite channel.
Transmission Rates
The DAMA equipment accepts encrypted data
streams from independent baseband sources and
combines them into one continuous serial output data
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