What is the process of superimposing information upon a carrier called?

The process of superimposing information upon a carrier is known as modulation. In telecommunications, modulation is the technique used to encode the information signal onto a carrier wave, which allows the signal to be transmitted efficiently over a distance. By manipulating properties of the carrier wave, such as its amplitude, frequency, or phase, the information can be encoded in a way that makes it suitable for transmission through various media.

This technique is essential because it allows signals to travel over long distances without significant degradation, facilitates the use of multiple signals over the same medium, and increases the overall efficiency of the communication system. For example, amplitude modulation (AM) or frequency modulation (FM) are common forms of modulation used in radio broadcasting.

In contrast, demodulation refers to the process by which the original information is extracted from the modulated carrier wave at the receiving end. Transmission describes the act of sending the modulated signal over the communication medium. Encoding typically refers to the conversion of information into a specific format for processing or storage, but does not specifically address the superimposition onto a carrier. Thus, modulation is the appropriate term for the process described in the question.