Figure 179: Br-Arch-2 Base Radio - Functional Block Diagram - Motorola MTS LiTE Installation, Configuration And Basic Service Manual

6802800U74-AN
Chapter 10: Base Radio
Figure 179: BR-Arch-2 Base Radio – Functional Block Diagram
RJ45
RJ45
RJ45
RF1
RF2
DC-
RX front end
inj.
RF3
RX Metering
and control
Transceiver/Controller Board
PA board
Forward/
reverse
TX
power
meter
28V
7V
Conv.
12V
Conv.
28V
7V+28V
Supply
Upon the power-up, BRC bootloader begins to download application code from SC over the Ethernet
LAN. After successful download, the code is executed. Once the BRC application is started, it gets
configuration parameters from SC. The configured BRC application allows the Base Radio to perform
call processing functions.
Should any alarm conditions arise during BRC application, operation, they are reported to SC over
Ethernet LAN. Alarm conditions may also be verified locally through the Service Access port linked to a
service computer using the get alarms MMI command.
The Base Radio operates in a TDMA (Time Division Multiple Access) mode. This mode, combined with
voice compression techniques, provides an increased channel capacity ratio of as much as 4 to 1. Both
the receive and transmit signals of the Base Radio are divided into four individual timeslots. Each
receive slot has a corresponding transmit slot; this pair of slots comprises a logical RF channel.
The Base Radio uses single, dual, and triple diversity reception for increased talkback coverage area
and improved quality. The Transceiver contains a three-branch receiver section in which all receivers
are used for triple diversity reception.
All receivers within a given Base Radio are programmed to the same receive frequency. The signals
from each receiver are fed to the BRC where a diversity combining algorithm is performed on the
signals. The resultant signal is processed for error correction and then sent to the Site Controller
through the Ethernet LAN with the appropriate control information regarding its destination.
The transmit section of the Base Radio is comprised of the Exciter (EXC) and Power Amplifier (PA).
The EXC processes the information to transmit from the BRC in the proper modulation format. This
322
CP2 Circuit
Ethernet
RS232+ trig In/Out
RX I&Q
RX I&Q
RX Back end
RX I&Q
Abacus III
CONGO
PLL
Exciter
Interface
Metering
and control
Baseband
RODINIA
filter
Feedback
Circulator
Coupler
7V,28V
Flash RAM
BUS
Interface
SPI FPGA
16.8MHz
16.8MHz
Osc.
TX I&Q
Synthesizer
PLL
JAVELIN
Driver
PA Driver
Pa Metering
and control
Host
P1021NXE2DFB
Trig In/Out
DSP
TMS320C6455
SPI
Supply
&Ctrl
7V,12V,28V
Exc.
Pwr
Out
Detector
Exc.
In
Variable
PA
step Att. feed
back
Variable
PA
step Att.
in
Supply
&Ctrl