2: System Overview
2-10
PRC1099A-MS
Display Board
Backlight
Generator - U3
N/A
Turns on the LCD backlight
Inputs 189 kHz clock signal from
the display driver U1.
Outputs square wave to LCD
display through step up
transformer T1.
Serial Decoders
and Segment
Drivers
N/A
Drives data to the front panel
LCD.
Inputs serial data from the
processor on the Processor
board.
Outputs parallel data to the LCD
display.
Junction Board
+5V Switch
Regulator - U1
N/A
Converts sw12V to +5V
supply voltage.
12V from the battery
through the front panel jumper on
the Accessory connector and the
front panel Power switch.
O5V supply voltage to the
various boards.
+8V Regulator -
U2
N/A
Converts sw12V to +8V
supply voltage.
12V from the battery
through the front panel jumper on
the Accessory connector and the
front panel Power switch.
Output to +8V supply voltage to
the various boards. Supplies T8V
in transmit mode and R8V in
receive mode.
DC Clamps T8 to
R8 - Q1, Q2
Transmit
Q1 clamps R8 to ground.
Inputs T8 line from Audio/Filter
board.
Receive
Q2 clamps T8 to ground.
Inputs R8 line from Audio/Filter
board.
Table 2-1 Board Functionality (continued)
Function
Path
Description
I/O