Digital audio broadcasting

Digital audio broadcasting transmits radio programs as encoded digital signals. Terrestrial systems such as DAB multiplex several services into a shared radio-frequency channel.

Digital audio: Sound represented as numerical samples or other discrete digital data. Broadcast systems encode program audio into digital data before transmission.
Radio broadcasting: One-to-many transmission of audio programs by radio waves to receivers. Digital audio broadcasting preserves radio's one-to-many delivery model while changing its signal format.
FM broadcasting: Analog radio broadcasting that conveys audio by varying a carrier's frequency. FM is the familiar analog alternative to DAB terrestrial transmission.
Digital radio receiver: A radio device that demodulates and decodes digital broadcasts into audio and associated information. Receivers turn DAB multiplexes into selectable programs and playable sound.
Digital cliff effect: The abrupt loss of usable digital reception when signal quality falls below a decoding threshold. DAB can sound clean within coverage, then fail suddenly where signal strength becomes insufficient.
Audio codec: Software or circuitry that encodes and decodes digital audio, often reducing its data rate. Codecs such as MPEG Audio Layer II compress programs to fit multiplex capacity.
Digital modulation: Encoding digital information onto a carrier wave by varying its properties. DAB maps encoded program data onto radio-frequency carriers for transmission.
HD Radio: A digital radio system that adds digital audio alongside analog AM or FM broadcasting. HD Radio uses hybrid analog-digital transmission rather than DAB's distinct ensemble approach.
Single-frequency network: A network of transmitters broadcasting the same signal on the same frequency in a coordinated manner. DAB can synchronize transmitters on one frequency to extend coverage efficiently.
Multipath propagation: Radio reception in which signals arrive by multiple reflected or scattered paths. DAB's modulation and guard intervals help tolerate reflections that disrupt reception.

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