User Manual

18 Chapter 6: Brief Technical Description GWMT Transmitter Manual
The power amplifier is protected from high VSWR loads by an isolator at its output. The PA also
provides a temperature sense signal to the controller, which disables transmission if temperature
is excessive.
The transmitter is designed to operate from a nominal 12 VDC source. A DC-DC converter is
included to convert the 12 V input to 24 V required for the PA. Circuitry senses the input DC
voltage, and disables the transmitter if an under voltage or over voltage condition is detected. The
transmitter also contains a universal input AC power supply. Its 12 VDC output is connected to
the DC power input via a jumper in the AC power cable.
The transmitter is controlled by a PIC micro-controller. This accepts keypad input and outputs
data to the synthesizer, digital to analog converters, and the front panel liquid crystal display. The
micro-controller also monitors several diagnostic inputs, and disables transmission if an error is
detected. An RS-232 interface is also provided, which is used during unit calibration.