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ADV7181D, Video Noise

Question asked by -=Steve=- on Jun 15, 2015
Latest reply on Jun 16, 2015 by DaveD

Hi,

 

I'm having some video noise issues with an ADV7181D design which is decoding a single composite video signal (on AIN10). From the attached video you can see colour corruption, and line synchronisation problems.

 

Power supplies all have <30mVp-p of noise, and the video signal on the input pin to the device looks clean. The clamping circuit on the ADV appears to be working and the video signal is within the ADC range of the device.

 

The ADV is connected to a Freescale IMX53 processor running Linux with a slightly modified driver to setup the I2C registers as per the evaluation software. The video data connection is 8bit YPrPb 4:2:2 format.

 

Initially I thought this was a clock issue and swapped out the 3V3 oscillator for a crystal and I get the same result. I've pulled off and measured the ELPF filter components which are all ok.

 

Any thoughts on what I should be looking at?

 

Thank you

Regards

Steve

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