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ADV7403 artefacts in video

Question asked by mvh on Apr 30, 2015
Latest reply on May 5, 2015 by DerekBurke

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.

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