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(ADV7180)Burst signal level

Question asked by donadona999s on Sep 19, 2017
Latest reply on Sep 21, 2017 by donadona999s

Hi !

 

Our customer have some problem at their application.

The project is already MP and it is automotive application.

One of their unit was fail at their OEM test line.

It looks like there is no color.

* Sorry I can't attach the picture here because it include confidential information.

We asked them to read back the register.

And the different was this.

So it is not color kill mode.

But it look like ADV7180 miss detect the video standard.

* Just only one ADV7180 has this problem.

   They already did cross check at their PCB.

And when they use short cable from camera, The color looks OK.

But when they use long cable(5m) , the picture change to no color.

The NTSC waveform is this.

With short cable.

 

With long cable.

.

 

It looks burst signal level is very low.

So my questions are these.

 

Q1)

At ADV7180 datasheet, it says ADV7180 can detect 5%~200% burst signal level.

 

I think color burst signal 100% for NTSC is 285mVpp.

Does this specification mean ADV7180 can detect the color burst signal if the burst signal level is 285*5%=14.275mVpp even if other signal level is 100% level( Ex. sync signal = 40IRE).


Q2)

Do you think this problem reason is ADV7180?

 

Q3)

Do you have any comment to debug this problem?

Our is it faster way send this device to quality team?

 

Best regards

Kawa

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