What does the microphone produce in an FM transmitter?

A microphone's fundamental job is to act as a transducer, converting the mechanical energy of sound waves into weak electrical signals. In an FM transmitter, this low-level audio signal is first fed into a speech amplifier. The speech amplifier boosts the weak electrical signal from the microphone to a level strong enough to drive the modulator properly. This step is critical before the signal is used to vary the frequency of the oscillator. Options suggesting the microphone produces radio frequency (RF) signals are incorrect because microphones only deal with audio frequency (AF) signals. The microphone also does not drive the oscillator directly; the signal must be amplified first.