modulation Definition

1. The act or process of, or an instance of, modulating something.

Thesaurus: shade, shift, intonation, inflection, accent, adjustment, alteration, pitch, sound, timbre, tuning.
2. technical
In radio transmission: the process whereby the frequency or amplitude, etc of a carrier wave is increased or decreased in response to variations in the signal being transmitted. See also amplitude modulation, frequency modulation.