Hello. We have an ADV7181C decoding a nonstandard sync-on-green video format that doesn't have serration during the vsync period. At room temperature and if you just leave it alone it works fine. Under some corner case and stress conditions, it occasionally screws up and drops a sync pulse and puts the DC restore clamp in a random spot for a few lines, always near the top of the frame. However, it never (rarely?...less often?...) makes a mistake if you take our weird format and just turn the serration back on.
Is there any calculation/justification for the 1nF AC coupling cap for the SOG/SOY input? What happens if I change it?