What is the primary function of a modulator in a radio system?

The primary function of a modulator in a radio system is to superimpose audio frequency onto a carrier wave. This process is essential for enabling the transmission of audio signals over long distances via radio waves. Modulation involves modifying the carrier wave's characteristics—such as its amplitude, frequency, or phase—based on the information signal (in this case, the audio frequency).

This allows the original audio signal to be transmitted effectively through the atmosphere, where it can be received and demodulated by a receiver, thus reconstructing the original sound for the listener. The ability to integrate the audio signal onto a carrier wave is critical for radio communication, as it ensures that the audio signal can travel over various distances and through different environmental conditions.

In contrast, while combining signals refers to mixing multiple signals, amplifying signals is focused on increasing their strength for improved transmission, and demodulating involves unpacking the information from a modulated carrier wave back into its original form. None of these functions capture the core role of a modulator in transforming the audio frequency signal into a suitable format for effective aerial transmission.