In an FM transmitter, the frequency multiplier:

In many FM transmitter designs, it is impractical to generate a very high-frequency, stable carrier signal directly at the oscillator. Instead, the oscillator generates a lower base frequency, which is then passed through one or more frequency multiplier stages. These multipliers step up the frequency by whole numbers (e.g., doubling or tripling it) until it reaches the desired final FM output carrier frequency. They also multiply the frequency deviation, giving the final signal the correct bandwidth. Distractors involving audio distortion or power supply load are incorrect because they describe the functions of the audio amplifier and the power amplifier, respectively.