AM demodulation is accomplished using which device?

AM demodulation is accomplished using which device?

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

Answer: (A)

In AM demodulation the goal is to recover the original audio by following the carrier’s envelope, since the information is carried in the amplitude of the carrier. An envelope detector does exactly this: a diode rectifies the RF signal and an RC network smooths it to produce a voltage that mirrors the modulating waveform. That recovered voltage is the audio you want. The other options aren’t suited for pulling out the modulating signal in AM. A discriminator converts frequency changes for FM, not amplitude variations. A limiter hardens the signal’s amplitude to a fixed level to stabilize FM demodulation, which would erase the AM envelope you need. A mixer shifts frequencies but doesn’t directly recover the baseband audio from the AM envelope. So the detector is the component that accomplishes AM demodulation.

In AM demodulation the goal is to recover the original audio by following the carrier’s envelope, since the information is carried in the amplitude of the carrier. An envelope detector does exactly this: a diode rectifies the RF signal and an RC network smooths it to produce a voltage that mirrors the modulating waveform. That recovered voltage is the audio you want. The other options aren’t suited for pulling out the modulating signal in AM. A discriminator converts frequency changes for FM, not amplitude variations. A limiter hardens the signal’s amplitude to a fixed level to stabilize FM demodulation, which would erase the AM envelope you need. A mixer shifts frequencies but doesn’t directly recover the baseband audio from the AM envelope. So the detector is the component that accomplishes AM demodulation.