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ADV7611 i2s audio problem

Question asked by dbolshakov on Oct 2, 2014
Latest reply on Oct 6, 2014 by mattp

We have a technical issue with the ADV7611 i2s audio.

The ADV7611 i2s audio bus on our custom board is connected to our SoC chip, which captures audio from i2s and plays/encodes it.

And we've got some strange issue with ADV7611 i2s audio signal during tests.

Sometimes we get some noise on the audio signal - a sort of loud static that overlaps the actual audio content (the actual audio still can be heart with the noise).

 

We've made some search on AD EngineerZone and found a thread which discusses some similar problem:

https://ez.analog.com/message/118874#118874

 

But in our case the appearance of the noise depends from the video content.
We've found that the noise comes only if the video has some constant white areas at the top of and in the bottom of the picture.

This can be also observed on ADV7611 AP signal (i2s data pin) - there is also some little noise overlapped with audio data which appears only together with the white areas at the top of and in the bottom of the picture.

 

We've captured the output of the ADV7611 to TS container. So, you can see the issue there:

http://elium.de/files/download/adv7611/adv7611_audio_issue.ts

 

Can someone help?

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