An interval signal is a characteristic sound or musical phrase used in international broadcasting and by some domestic broadcasters. It serves several purposes:
- It assists a listener to tune his or her radio to the correct frequency for the station.
- It informs other stations that the frequency is in use.
- It serves as a station identifier even if the language used in the subsequent broadcast is not one the listener understands.
BBC World Service in English: Bow BellsBroadcasting Services and Interval Signals
Radio Australia: Chorus of Waltzing Matilda on chimes
Radio Canada International: First four bars of O Canada played on a piano
Radio France Internationale: Electronic-disco, cumulating in the last 8 measures of the Marseillaise
Radio Moscow (former service of the Soviet Union): Moscow Nights
Voice of America: Yankee Doodle played by a brass band
Voice of Russia: Chime version of chorus from Muggorsky's Pictures at an Exhibition