What does modulation in telecommunications primarily involve?

Modulation in telecommunications primarily involves varying a carrier signal to encode a message. This process is essential for transmitting information over various communication channels, such as radio waves, where the characteristics of the carrier signal—such as amplitude, frequency, or phase—are altered to embed the data being sent.

By modulating the carrier signal, the original information can be transmitted over long distances and can be decoded by the receiving equipment. The modulation process allows the same frequency range to carry multiple signals and improves the efficiency of bandwidth usage, which is crucial in telecommunications.

The other options focus on different aspects of communication and data management. Adjusting video and audio quality pertains to enhancing media playback rather than the fundamental transmission mechanism. Transmitting data over satellite signals is a method of communication but depends on modulation among other factors. Lastly, creating backup copies of data relates to data storage and protection, rather than the process of sending that data through a medium.