What is the main purpose of signal modulation?

The main purpose of signal modulation is to encode information onto a carrier wave for transmission. Modulation involves varying some characteristic of the carrier wave—such as its amplitude, frequency, or phase—in accordance with the information signal being transmitted. This process is crucial for efficiently sending information over distances, especially in communication systems like radio, television, and cellular networks. By modulating the carrier wave, the information can be transmitted at a frequency that is suitable for the transmission medium, allowing it to travel further and with less interference.

The ability to encode information on a carrier wave also means that multiple signals can be transmitted simultaneously over the same channel through different modulation schemes, achieving better utilization of the available bandwidth. This is vital in modern communication systems, where bandwidth is a limited resource.