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Graham's Line Ident Tone System


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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.


Graham's Line Ident Tone System (GLITS) is a test signal for stereo systems devised by BBC TV Sound Supervisor and Fellow of the IBS 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.


This arrangement has an advantage over the EBU stereo ident tone in that each channel is explicitly identified as belonging to a stereo pair. The EBU Technical Document Multichannel Audio Line-up Tone (Tech 3304) defines stereo lineup tone has having an interruption in the left channel only, lasting 250 ms every 3 s.


There has always been debate about the expansion of the GLITS acronym. Graham Haines has been asked and says that the acronym was actually invented by Ray Angel (formerly BBC Senior Sound Supervisor in Television Studios, heavily involved in the development of stereo techniques in TV in the early days) and expands to: Graham's Line Ident Tone System.


From Institute of Professional Sound (IPS)

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