Signal

Information being measured, transmitted or received via any medium. In terms of sound, it may be a sound to which one wishes to listen, or an electrical representation of a sound (audio signal) which is being recorded or reproduced (as with a microphone, tape recorder and magnetic tape, or a disc recording), transmitted or broadcast (as with radio), or synthesized electronically or by means of a computer (see sound synthesis).

In any of these systems, the signal must be distinct from the noise (which is the opposite or complement of the signal) in order for information to be fully received. For instance, the television signal must be distinguishable from the 'snow' or interference, the sound signal on magnetic tape from the tape hiss. Although a digital recording of information in the form of binary numbers may be regarded as a signal free of noise (but subject instead to errors or other forms of digital distortion), if it represents a sound, it can only be heard if it is converted to an audio signal.

See: Background Noise, Carrier, Channel, Dropout, Feedback, Print-Through, Radio Spectrum, Separation, Signal-to-Noise Ratio, Switch, Transmission. Compare: Communication, Message.

See sound signal for the use of this term in soundscape studies.