modulate (v.)

1610s, in music, back-formation from modulation, or else from Latin modulatus, past participle of modulari "regulate, measure off properly, measure rhythmically; play, play upon," from modulus "small measure," diminutive of modus "measure, manner" (from PIE root *med- "take appropriate measures"). General sense from 1620s. In telecommunications from 1908. Related: Modulated; modulating.