CurtPalme.com Home Theater Forum

[virusc]

The only devices mentioned that may have tri level sync in all of the barco manuals I have reference HDTV production equipment and special players. Does anyone use it? What is the real difference and compatibility with regular composite and HV sync?

thanks,

Nate

[beun]

Tri level sync is the standard for hi-def video signals. The old bi-level sync is a negative going pulse only, the tri-level sync first goes negative and then positive with the rising edge as the reference edge and the start of line at the zero crossing.

The main differences are as follows:

1) The sync itself contains no DC. This is touted as a big advantage although I don't see it, the video signal itself already contains DC.
2) The tri-level sync should now be present on all three channels although any equipment I know of only looks at the Y or G signal.
3) The pulses are way narrower than the old bi-level sync and therefore may not be detected by older sync separators (even if they could process the HD video).

Some more information: http://www.extron.com/company/article.aspx?id=ta062002

[virusc]

OK thanks,