In communication systems, what is the term 'carrier wave' referring to?

The term 'carrier wave' refers to a wave that can carry various forms of information and is modulated to transmit data. In communication systems, a carrier wave is typically a waveform created at a specific frequency that acts as the base signal. Through modulation techniques, such as amplitude modulation (AM) or frequency modulation (FM), the carrier wave is altered to encode information, enabling the transmission of audio, video, or data over distances. This versatility in carrying different types of information is fundamental to various communication protocols and media.

While some options touch on aspects of carrier waves, they either limit the definition or provide inaccurate contexts for their use. For instance, defining it as a frequency only for digital signals disregards the analog applications. Similarly, stating it is only used in FM modulation excludes its relevance in other modulation techniques. Lastly, mentioning waves emitted by antennas without signals does not capture the essence of a carrier wave's role in active communication, as it inherently involves transmitting information.