The transmission of a fixed frequency that has been altered (modulated) to "carry" data. The frequency is measured in Hertz (cycles per second). For example, the 2.5 GHz (gigahertz) Wi-Fi band means that a radio wave of 2.5 billion cycles per second is transmitted. The receiving device detects the steady 2.5 GHz carrier and demodulates it to obtain the data within.
Carrier frequencies were created for wireless radio transmission, but they are also used for wired connections in order to send separate signals down a single pathway (see
FDM). See
modulation,
carrier and
Hertz.