When using the ADV7802 with a 1080i source, it was noticed that there is a large amount of jitter, after the VBI region of the video. This jitter is affecting sensitive backend device.
This noise does not appear to be board/or noise coupling.
The ADV7802 contains coast features which allow it to coast/free-run in the event of missing sync or non-standard input.
The coast feature is automatically enabled , however manual controls are available.
0xCC - COAST_MAN_EN
This control overrides the automatic values and uses.
This bit changes the coasting mode into a manual mode and also changes the coasting so that it coasts on all lines. Auto mode is only coasting on active video.
0xCC – COAST_MAN allows you to use manual controls.
0xCC[5:4] – Coast lock
2'b00 = 15 lines
2'b01 = 31 lines
2'b10 = 63 lines
2'b11 =127 lines
In the question above, the PLL needs to reacquire after active video is recieved, ehich is leading to jitter.
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