Hi Dave,
Thanks a lot. I just talked to our hardware guy. He checked the input to ADV7180, and it is clean. Plus the video output of PAL doesn't have such issue.
If there is a noise(ie. ground loop) in ADV7180 part that affects the syncs, is it possible that the video output of PAL is still correct?
One thing still making no sense to me is why PAL is perfect, while NTSC has this issue?
Phil