TX RX Systems Inc. Manual 7-9487-3 05/05/11 Page 3
arresters (see
Figure 1
). The specifications for the
tower box are listed in
Table 2
.
Base Control Unit
The ground-mounted Base Control Unit is intended
for 19-inch rack mounting. It houses alarm indica-
tors, a power supply or DC to DC converter, and a
display panel to provide visual feedback on the
system’s operating status. There is also a test port
input for providing an RF signal path for loopback
tests. The front panel display shows status infor-
mation such as amplifier current draw and temper-
ature. In addition the display is used to provide a
user interface for adjustments such as setting
reserve attenuation. The current draw values of
each amplifier in the system is displayed by the
base control unit. Also included in the system is a
Webpage User Interface for controlling and moni-
toring of amplifier currents, alarms, and attenua-
tors. The webpage user interface is accessed
through the front panel LAN connector. Refer to
Appendix A
for instructions on accessing this fea-
ture. A photograph of the front panel is shown in
Figure 2
.
BASE CONTROL UNIT STYLES
The base control unit is available in two styles
including the Multicoupler Control Unit (MCU) and
the Control Management Unit (CMU). The tower
top box used in your system is the same regard-
less of which style base control unit you have. The
front panel of your base control unit is the same for
both MCU and CMU styles.
MCU
The MCU style base control unit is designed to
include a receiver multicoupler function in addition
to the base controlling functions. The MCU has the
built-in capability to split the received RF signal
from the tower top box to 16 individual receivers. In
addition, there is also an expansion port which
allows the additional expansion of the system up to
32 ports. The specifications for the MCU are listed
in
Table 3
. A top view and a back view of the MCU
deck are shown in
Figures 3 and 4
respectively.
FUNCTIONAL BLOCK DIAGRAM
The functional block diagram of the system is
shown in
Figure 5
. RF signals enter the tower top
box and are passed thru a multi-resonator prese-
lector tuned to pass 792 to 824 MHz. After filtering
the signals are amplified by the active tower top
LNA (either amp A or B depending on user selec-
tion) before passing through the main transmission
line to the ground based control unit. The input of
each tower top LNA has a test signal port which
allows test signals from the base control units front
panel test port to be coupled into the systems RF
signal path. There is a 33.5 dB loss associated with
test signals injected into the system. The user has
Figure 2:
Front view of the Base Control Unit.
Note: Both the MCU and CMU style base control units use the same front panel.
Status LED’s
Contrast
Adjust
Up
Button
Cancel
Button
LAN
Port
Amplifier
Select
Buttons
Display
Down
Button
Enter
Button
Test
Port
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