In sonar systems, a device (a) that is used to detect acoustic waves, such as those produced by ships and submarines, (b) that, when activated, relays information by radio, (c) that may be active or passive, and (d) that may be directional or nondirectional. [From Weik '89]

See sonar.

See acoustic wave.

A telephone in which the operating power is derived from the speech input only.

A station equipped with an ionosphere sounder for realtime monitoring of upper atmosphere phenomena or to obtain data for the prediction of propagation conditions. [NTIA]

In automated HF radio systems, the broadcasting of a very brief signal, containing the station address, station identifier, or call sign, to permit receiving stations to measure link quality.

In communications, that part of a system from which messages are considered to originate.

In optical systems, the ratio of emitted optical power of a source to the input electrical power.

In computing, data processing, and communications systems, a language from which statements are translated.
Note: Translators, assemblers, and compilers prepare target language programs, usually machine-language programs, from source language programs, usually high-level language programs written by programmers.

1. A computer program written in a source language.
Note: An example of a source program is a program that serves as the input to an assembler, compiler, or translator.
2. A computer program that must be assembled, compiled, or translated before it can be executed by a computer. [From Weik '89]