User's Manual

Technalogix Ltd TAVD-500 Transmitter
VI-3
Aside from taking readings from the coupler, the microcontroller on the coupler conditioning
module also interfaces with the RF Conditioning module (through J201) and the Temperature
Sensor (through J202). The microcontroller interfaces with the system CAN bus using U203
and U204. Through the CAN bus, the Coupler Conditioning board is able to communicate with
the User Interface module, and any other amplifier enclosures that are in the system.
The last task of the Coupler Conditioning board is to send and receive remote access signals to
and from the TxNET board. Two analog outputs, proportional to forward and reflected power
and produced by the digital-to-analog converter U207 after it receives input from the
microcontroller. The analog outputs are then buffered by U206 before being sent through J208
and J209 to the TxNET board. J208, along with J209, also bring the digital inputs and outputs
from the TxNET board to the Coupler Conditioning module. The digital signals are then
connected to the microcontroller through the opto-isolators U209 through U213.
RF Conditioning Module
The RF Conditioning board is located at the RF input of the amplifier. Its main function is to act
as a variable attenuator, so that the control system can add attenuation to the input of the
amplifier in order to limit the output power of the transmitter. The RF signal comes in to the RF
Conditioning module through J301 before it passes through a fixed attenuator (Pi-network)
made up of R301, R302, and R303. The signal then passes through the digitally-controlled
variable attenuator U302 before exiting through J303. The input control for the digital attenuator
comes from the Coupler Conditioning module through J304. The input signals are passed
through the opto-isolators U302, U303, and U304 before being sent to the digital attenuator. In
total, five control signals go to the digital attenuator, allowing for attenuations of up to 31dB in
1dB steps.
Temperature Sensor Module
The Temperature Sensor module is a small board mounted to the main heatsink of the amplifier.
The main purpose of the temperature sensor module is to take temperature readings of the
heatsink. The temperature sensor IC is U701 which, after it has taken a reading, relays the
digital information to the Coupler Conditioning module through J702. Also passing through
J702 is a driver disable signal coming from the Coupler Conditioning module. The Temperature
Sensor module simply takes this signal and passes it through to a pad, where a wire connects it
to the driver pallet.