In an FM radio receiver, which component is used to demodulate the signal?

In an FM radio receiver, which component is used to demodulate the signal?

• A. Discriminator
• B. Detector
• C. Limiter
• D. Mixer

Answer: (A)

FM demodulation hinges on turning frequency changes into a usable audio signal. A discriminator does exactly that: it responds to instantaneous frequency deviations of the FM carrier and produces an output voltage proportional to those changes, which becomes the audio you hear. In the receiver chain, the signal is first limited to remove amplitude variations so the frequency information isn’t masked, and then fed into the discriminator to recover the audio. The other components serve different roles. A limiter only removes amplitude fluctuations; a mixer shifts frequencies to an intermediate stage; an envelope detector (the typical detector for AM) would follow the carrier’s amplitude, which in FM carries no information, so it can’t demodulate the signal.

FM demodulation hinges on turning frequency changes into a usable audio signal. A discriminator does exactly that: it responds to instantaneous frequency deviations of the FM carrier and produces an output voltage proportional to those changes, which becomes the audio you hear. In the receiver chain, the signal is first limited to remove amplitude variations so the frequency information isn’t masked, and then fed into the discriminator to recover the audio.

The other components serve different roles. A limiter only removes amplitude fluctuations; a mixer shifts frequencies to an intermediate stage; an envelope detector (the typical detector for AM) would follow the carrier’s amplitude, which in FM carries no information, so it can’t demodulate the signal.