What is the meaning of 'amplitude modulation (AM)'?

Amplitude modulation (AM) is a technique used in electronic communications, most commonly for transmitting information via a radio carrier wave. In AM, the information is encoded by varying the strength (or amplitude) of the carrier wave in accordance with the information signal. This means that as the amplitude changes, it reflects the fluctuations in the source signal, such as audio or other types of data. The variations in amplitude allow the information to be conveyed to the receiver, which demodulates the carrier wave to retrieve the original signal.

This method contrasts with other modulation techniques, such as frequency modulation (FM), where the frequency of the carrier wave is varied instead of the amplitude. Understanding this distinction is crucial because it highlights the fundamental operation of AM and its role in radio transmission and other communication systems, which rely on the ability to modulate and demodulate signals effectively.