'''Signal transition''':, when Inreferring to the [[modulation]] of a [[carrier wave|carriersignal]], is a change from one [[significant condition]] to another.
''Note 1:'' Examples of [[Signalling (telecommunication)|signal]] transitions are a change from one electricalelectric current, voltage, or [[Power (physics)|power]] level to another; a change from one optical power level to another; a [[Phase (waves)|phase shift]]; or a change from one [[frequency]] or [[wavelength]] to another.
''Note 2:'' Signal transitions are used to create signals that represent [[information]], such as "0" and "1" or "[[mark frequency|mark]]" and "[[space frequency|space]].".
