GLiTS

Graham's Line Identification Tone System (GLITS) is a test signal for stereo systems devised by BBC TV Sound Supervisor and Fellow of the IPS Graham Haines in the mid 1980s. It comprises a 1 kHz tone at 0 dBu (-18 dBFS) on both channels, with interruptions which identify the channels.
The left channel is interrupted once for 250 ms every 4 seconds. 250 ms later the right channel has two interruptions of 250 ms spaced by 250 ms.
This arrangement has an advantage over the EBU... meer