TX RX Systems 434B-83H-01-M-110/48, Инструкция по установке и эксплуатации

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TX RX Systems Inc. Manual 7-9547-1 12/09/14 Page 9
reporting and form-C contact switching for alarm
integration. Included in the tower top box is a pre-
selector filter, amplifier “A” and amplifier “B,” switch-
ing circuitry, control board and lightning arresters
(see
Figure 1
). The specifications for the tower box
are listed in
Table 2
. The specifications for tower
box wind loading are listed in
Table 3
.
Base Control Unit (MCU)
The ground-mounted Base Control Unit (also
called an MCU) is intended for 19-inch rack mount-
ing. It houses alarm indicators, 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 dis-
play shows status information such as amplifier
current draw and temperature. In addition the dis-
play is used to provide a user interface for adjust-
ments such as setting TTA Net Gain attenuation.
The current draw values of each amplifier in the
system is displayed by the base control unit. The
front panel of the base control unit is shown in
Fig-
ure 2
.
The base control unit design includes a receiver
multicoupler function in addition to the system con-
trol and monitoring functions. The deck has the
built-in capability to split the received RF signal
from the tower top box to 16 individual receivers. In
addition, there is an expansion port available which
allows expansion of the system up to 32 ports. The
specifications for the base control unit are listed in
Table 4
. The top and rear views of the base control
unit are shown in
Figures 3 and 4
respectively.
FUNCTIONAL BLOCK DIAGRAM
Figure 5
is a functional block diagram of the entire
TTA system which includes the tower top box and
the control deck. RF signals enter the tower top
box through the antenna port and are applied to
either the A or B tower top LNA. When the system
is in the bypass mode signal flow is around the
amplifiers. Signals are output from the tower top
box at the main port and travel down the main
transmission line to the main port of the base con-
trol unit. As noted on the block diagram, the main
transmission cable also carries DC operating volt-
age up to the tower box and provides a conduit for
serial communications between the processors in
the tower box and the base deck.
RF signals enter the main port of the base control
unit deck and are routed to the optional preselector
port on the rear of the unit. This connection pro-
vides an easy way for the customer to add a nar-
rowing filter to the signal path of the system. If an
optional narrowing filter is not used then a loop
back cable must be installed to insure RF continuity
through the system. Upon re-entering the deck the
RF signals are input to the base amplifier assem-
bly. The amplifier assembly provides bandpass fil-
tering, attenuation, amplification, and signal
splitting. The signal splitter feeds a 16-way splitter
Figure 2:
Base Control (MCU) Unit front panel.
Status LED’s
Contrast
Adjust
Up
Button
Cancel
Button
Amplifier
Select
Buttons
Display
Down
Button
Enter
Button
Test
Port
LAN
Connector
Note:
The SNMP feature is
accessed through this port.
Refer to the section of this
manual titled SNMP Notifi-
cations for details on the
use of this feature.