Users Manual Part 2

Figure 180: BR-Arch-2 Base Radio – Functional Block Diagram
RJ45
RJ45
CP2 Circuit
Ethernet
Flash
RX front end
RX Metering
and control
CONGO
PLL
16.8MHz
Osc.
RX Back end
Abacus III
Interface
Interface
Exciter
Metering
and control
RODINIA
JAVELIN
Baseband
filter
Driver
Driver
FPGA
DSP
TMS320C6455
Host
P1021NXE2DFB
PATX
7V+28V
Supply
7V
Conv.
28V
28V
7V,28V
7V,12V,28V
SPI
12V
Conv.
Feedback
Coupler
Circulator
Forward/
reverse
power
meter
Pwr
Detector
Exc.
Out
PA
in
Pa Metering
and control
Variable
step Att.
Variable
step Att.
Supply
&Ctrl
Supply
&Ctrl
Exc.
In
RAM
RS232+ trig In/OutRJ45
RF2
RF1
RX I&Q
RX I&Q
RX I&Q
16.8MHz
TX I&Q
SPI
BUS
Trig In/Out
RF3
DC-
inj.
Transceiver/Controller Board
PA board
Synthesizer
PLL
PA
feed
back
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.
6802800U74-AP
Chapter 10: Base Radio
349