Figure 4-15.—The AN/USQ-59 mode control panel.
and input to the computer. Link-11 uses the half-
duplex mode.
SIDEBAND SELECT SWITCH —When the
SIDEBAND SELECT switch is placed in the LSB or
USB position, the DTS processes only the lower
sideband or upper sideband of the received signal.
When the switch is in the DIV position, the DTS
combines both the upper sideband and the lower
sideband signals to create frequency diversity data for
input to the computer. When the switch is in the
AUTO position, the DTS selects the signal with the
best receive quality for processing. The AUTO
position is the normal position of this switch.
DATA RATE SWITCH —Selects the data rate
that the data converter uses. When the switch is in the
DUAL 1200 position, the data converter can transmit
and receive two unrelated streams of data at 1200 bps.
In the 1200 and 2400 positions, the data converter
4-14
transmits and receives a single data stream at 1200
and 2400 bps, respectively. When the switch is in the
TADIL A position, the data rate is controlled by the
DATA RATE switch on the TADIL A control panel.
The TADIL A position is the normal position for
Link-11.
SYNC MODE SWITCH —The SYNC MODE
switch selects the mode of synchronization used by
the DTS receive circuitry and is used in conjunction
with the TIMING STORED/CORRECTED switch on
the TADIL A control panel. The normal operating
position for the SYNC MODE switch is in the
FAST/CONT position.
When the switch is in the FAST/CONT position,
both the fast and continuous synchronization circuits
of the DTS are selected. Synchronization is initially
obtained during the five-frame preamble and
maintained continuously during the data portion of the
transmission. The TIMING switch on the TADIL A
control panel must be in the CORRECTED position.
W h e n t h e F A S T p o s i t i o n i s s e l e c t e d ,
synchronization is only during the five-frame
preamble. If the CONT position of this switch is
selected, only the continuous synchronization circuits
are selected. Synchronization is obtained only during
the data portion of the transmission. The TIMING
switch on the TADIL A control panel must be in the
CORRECTED position for both of these modes.
The INHIBIT position of this switch disables both
the fast and continuous synchronization circuits of the
DTS. The DTS will maintain the time base that was
stored when the switch was turned to INHIBIT. For
synchronization to be held, the unit with its sync
mode inhibited must maintain its original geographic
relationship to all other units in the net. This position
is used when the received signal contains interference
that could cause loss of synchronization.
OPERATE/SELF-TEST SWITCH — T h is
switch must be in OPERATE for normal on-line
operations. When the switch is placed in the SELF-
TEST mode, the DTS is placed in an off-line mode
and the fault isolation circuitry is enabled.
