Which modulation method involves varying the amplitude of a carrier in line with the intelligence to be transmitted?

The modulation method that involves varying the amplitude of a carrier signal in accordance with the information being transmitted is Amplitude Modulation (AM). In this technique, the amplitude of the carrier wave is modified to represent the changing signal levels of the information. Consequently, as the information signal (or intelligence) increases or decreases, the amplitude of the carrier wave increases or decreases correspondingly. This characteristic allows AM to effectively convey audio signals, such as those used in radio broadcasting.

The significance of this approach lies in its simplicity and ease of implementation in transmitting audio over the airwaves. However, AM is also more susceptible to noise and interference, which can affect the clarity of the received signal. Understanding this modulation method is fundamental as it lays the groundwork for more advanced techniques in communications.