What term is an electromagnetic wave modulated to convey a signal?

• A. Carrier Wave
• B. Datalink
• C. Transceiver
• D. Antenna Gain

Answer: (A)

Modulating an electromagnetic wave to convey a signal relies on a carrier wave. The carrier is a stable high-frequency waveform that carries the information by varying its amplitude, frequency, or phase according to the data. This modulation lets the information ride on the wave as it travels through the medium, creating a transmitted signal that can reach receivers. The carrier provides the vehicle for the information; without it, the data wouldn’t be easily transmitted over distance. Other terms describe broader concepts or hardware—datalink refers to the data transmission system as a whole, a transceiver is the device that both transmits and receives, and antenna gain describes how effectively an antenna radiates in a given direction—none of which define the specific wave that carries the encoded information.