2) Transmitter
1. Microphone Amplifier
The microphone amplifier IC301 has 2 operational amplifiers. The voice is converted into the electric signal through the microphone, and then supplied to IC301. The input signal is amplified and pre-emphasized to be output. [VHF] The signal output from microphone amplifier is adjusted the maximum frequency deviation at VR2. The adjusted signal is added to the cathode of VCO variable-capacitor D4 for deviation to change the capacity of the oscillation circuit resulting the FM deviation. [UHF] The signal output from microphone amplifier is adjusted the maximum frequency deviation at VR1. The adjusted signal is added to the cathode of VCO variable-capacitor D10 for deviation to change the capacity of the oscillation circuit resulting the FM deviation.
2. Power Amplifier
The oscillated signal at VCO is supplied to the power amplifier Q3, passing through buffer amplifier Q5, driver amplifier IC1. The power-amplified signal is supplied to the antenna through the duplexer after the harmonics are attenuated enough.
