VAL AVIONICS LTD
VAL AVIONICS LTD
VAL AVIONICS LTD
VAL AVIONICS LTD
AWOS 2000
AWOS 2000
AWOS 2000
AWOS 2000 –
–
–
– VHF TRANSMITTER
VHF TRANSMITTER
VHF TRANSMITTER
VHF TRANSMITTER
MAINTENCE AND REPAIR MANUAL
MAINTENCE AND REPAIR MANUAL
MAINTENCE AND REPAIR MANUAL
MAINTENCE AND REPAIR MANUAL
Revision 1
Page 5 of 13
April 2012
MAIN CPU
Internal frequency
– 8MHz
Modulation
Control
12V Power
Supply
(300kHz)
5V Power
Supply
(0Hz)
12V DC
5V DC
TX
Synthesizer
To Transmitter
XMIT LO
118 – 137MHz
To J4
XMIT
Key
XMIT
Power
VCO Enable
To Transmitter
J3/X1/X3/X5
To J4
Audio
Input
Modulation
AGC Sense
From TX
XMIT Enable
Figure 2:
AWOS2000 Mainboard Block Diagram
1.2.1.2 Power Supply Circuits
The power supply section of the main board supplies 12V for the transmitter and
5V for the microcontroller and audio circuitry. The unit is turned on and off by a
digital circuit operated by the left rotary encoder push button. The 12V power
supply is a self-contained module that outputs 12V ±10%. The 5V power supply
is also a linear regulator that outputs 5V ±5%.
1.2.1.3 Modulation Control
The audio section of the main board receives the audio input and regulates the
output to the transmitter board.
