Question 6A463

An FM receiver, while often a superheterodyne design, differs from its AM counterpart in several key aspects. A) **The method of detection:** AM receivers typically use an envelope detector, while FM receivers employ a frequency discriminator (like a ratio detector or PLL) to convert frequency variations into amplitude changes representing the audio. B) **The reduction of sensitivity to amplitude modulation:** FM receivers include limiter stages before the detector. These circuits remove any amplitude variations, effectively rejecting AM noise and interference, which is a significant advantage of FM. C) **De-emphasis:** FM broadcasting uses pre-emphasis at the transmitter to boost higher audio frequencies and improve the signal-to-noise ratio. The FM receiver must then apply de-emphasis, attenuating these frequencies back to normal to restore the original audio balance and further reduce high-frequency noise. Therefore, all these points highlight fundamental differences in an FM receiver's design and operation compared to an AM receiver.