Today I want to describe you a problem I’m faced with, using the ADV7403 with standard video signal ( PAL BG ) from a video camera.
I’m using the ADV7403 on a board, who’s purpose is the insertion of text and graphic into an existing video signal, e.g. from an inspection video camera.
The incoming video signal (standard definition, PAL or NTSC ) is transformed to digital video ( ITU-R BT656 ) by the ADV7403,
combined with the insertion data and retransformed to analog video, using the ADV7341.
In the past, we have widely used the FCB-EX-490DP Sony module. This model is producing a video signal, that has some phase – Jitter
( about 1 to 2 us ) on the csync, when the zoom function of the module is used.
This Jitter is small enough for an ordinary video monitor, to keep the effect invisible ( no artefacts ).
If passing the video signal through my insertion board, the csync – Jitter is magnified by a factor of 2…3, and now appears as artefacts on the video ( e.g. insertion text without color ).
Looking for the reason of the artefacts, I found the ADV7403 to be guilty: The ADV7403 performs the “sync separation” and outputs the signal “HSOUT” ( pin 4 ).
This HSOUT signal shows the magnified Jitter ( about 5 … 10 us ).
After thoroughly reading the “sync” subjects of the manual, I made numerous tests, programming the SDP registers that are involved
( e.g. register addresses 0x01, 0x14, 0x15, 0x34..36, 0x51 and so on ), but without success.
Perhaps you can help me to find out, if this problem can be solved.