The Xtal plays a critical role in the decoder performance. Attached is an application note that covers most aspects to be considered when choosing the xtal.
For qualification of an Xtal we advise the following,
1. Using the application note ensure that the correct load caps are chosen
2. Apply a nominal PAL or NTSC CVBS signal to the decoder with with part programmed in standard configuration
3. Start to step the colour sub carrier + away from it nominal frequency, note the frequency where colour lock is lost or becomes distorted
4. Repeat the check but this time for the - frequency
5. Analyze the results to ensure that they are within the value quoted on our datasheet and also symmetrical
Attachments:
5807.note_on_xtal_rev1.pdf