radio reception

Radio broadcasting is the transmission of electromagnetic radiation (radio waves) to receivers over a wide territory. Most broadcasts are audio (sound), sometimes with embedded metadata. Listeners need a broadcast radio receiver to pick up these signals. "Terrestrial" broadcasts, including AM, FM and DAB stations, originate signals from a land-based transmitter, while "satellite radio" signals originate from a satellite in Earth orbit.
Individual own programming, or are affiliated with a radio network that provides content, either in broadcast syndication or by simulcasting, or both. The most common transmission technologies are analog and digital signals. Analog radio uses one of two modulation methods: amplitude modulation, used by AM radio, or frequency modulation, for FM radio. A newer technique, digital radio stations, transmit using one of several different digital audio standards, such as DAB (Digital Audio Broadcasting), HD radio, or DRM (Digital Radio Mondiale).

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