The change in the amplitude of a wave over time is a characteristic of what?

The change in the amplitude of a wave over time is a defining aspect of amplitude modulation. This process involves varying the strength (or amplitude) of a carrier wave in relation to the information signal that is being transmitted. As the amplitude of the carrier wave changes, it encodes the information being sent. Amplitude modulation is commonly used in radio broadcasting, where the amplitude of a carrier wave is modulated to carry audio signals.

In contrast, harmonics involve the generation of frequencies that are integer multiples of a fundamental frequency, which does not specifically pertain to changes in amplitude over time. Phase modulation relates to variations in the phase of the carrier wave rather than its amplitude. Interference refers to the phenomenon that occurs when two or more waves overlap, resulting in a new wave pattern, and this does not inherently describe a change in amplitude of a single wave over time. Thus, amplitude modulation is the most accurate term to describe the observed change in amplitude of a wave over time.