Which statement best describes an analog signal?

An analog signal is characterized by its continuous variation in amplitude and time. This means that rather than representing data in discrete values like digital signals, an analog signal can take on an endless range of values. Think of sound waves, for example; the sound is not formed by distinct steps but by smooth and continuous changes in pressure.

This definition aligns well with various physical phenomena that we encounter in the real world, such as temperature variations, light intensity, and audio signals. Unlike digital signals, which are composed of binary values (0s and 1s) and operate at discrete levels, analog signals give a more complete representation of a range of information, making them suitable for applications that require nuances, such as audio and video transmission.

The other options do not accurately capture the essence of analog signals. Digital signals are explicitly defined as having discrete levels, and a computer error does not relate to the characteristics of signal types. Encrypted communication involves data transformation for security purposes, unrelated to whether the original data is transmitted as digital or analog. Therefore, focusing on their continuous nature is crucial to understanding where analog signals fit into the broader context of signal processing.