What is a frequency discriminator?

A frequency discriminator is a specific type of detector circuit used in radio receivers to recover the original audio from a Frequency Modulated (FM) signal. As the incoming FM signal's frequency shifts above and below the center frequency, the discriminator converts these frequency variations into proportional voltage amplitude variations, which is the recovered audio signal. While the word "discriminator" might sound like a filter that separates closely adjacent signals, in the context of radio architectures, it strictly refers to this FM demodulation stage. It is a receiver component, not a generator circuit, making the other options incorrect.