I'm currently trying to find an issue with a system we have developed that uses an ADV7802. The YC Auto mode fails with some s-video sources (different analog camera modules), where the s-video is detected as an composite instead. When we use a signal generator as source there is never any problems.
With a short cable between the input module where the ADV7802 sits and the camera module, is works reliably but when the cable length is increased with a couple of meters the ADV7802 starts to fail the detection of the s-video. With a signal generator we have no problem even with 60m cable.
I have checked the signal levels from the source with the automatic detection fails, and haven't found anything that could explain why the automatic detection of the C channels fails.
How does the YC Auto mode work? What is the different criteria that needs to be met for it to detect a source as an s-video or composite?
Any ideas what we should be looking for in the s-video signal that could cause the ADV7802 to fail the YC auto detection?
/BR Johan Karlsson