THEORY OF OPERATION POWER AMPLIFIER ASSEMBLY Driver Amplifier The driver amplifier section provides the following function. * Amplifies the output signal of the synthesizer. * Matches the low impedance of the power amplifier. * Provides some attenuation of harmonics. Power Amplifier The final power amplifier further amplifies this signal to the specified output level. Low Pass Filter The low pass filter provides the following functions: * Attenuates harmonics by approximately 50 dBm.
The VCO operates at the output frequency and is controlled by applying a voltage to the voltage variable capacitor. The oscillator is tuned to the center of the operating frequency range so the voltage on the capacitor is compatible with the output range of the low pass filter.
* Low Battery detection circuit * Low voltage reset circuit. * Serial communications circuit (RS-232).