How does Amplitude Modulation (AM) operate?

Amplitude Modulation (AM) operates by varying the amplitude of the carrier signal in accordance with the information or audio signal being transmitted. In this process, while the frequency of the carrier remains constant, its amplitude changes to represent the variations in the input signal. This allows the receiver to extract the original audio or data signal from the modulated carrier wave.

Amplitude modulation is particularly effective in radio broadcasting where audio signals are transmitted over the air. The amplitude changes correspond to the loudness of the audio, allowing amplitude modulated signals to carry sound information effectively.

The other options describe different modulation techniques or processes that do not correctly represent how amplitude modulation functions. For instance, varying the frequency of the carrier signal pertains to frequency modulation (FM), while maintaining a constant amplitude while varying frequency is characteristic of constant amplitude schemes. Likewise, demodulation is a separate process that involves retrieving the original signal from the modulated carrier and is not part of the modulation itself.