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Why PAL Video work good but RGsB Video does not?

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tanbakoo

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Hi
I have two video in my system one of them is PAL and other is RGsB (VGA 800*600 60Hz but CSync composite on Green[SOG])
When we have a noise around my system, PAL output has a good video quality but RGsB output does not has a good video quality and video on display is not stable.

What is reason of this difference ?
How can I solve it to have a stable RGsB video output ?

- - - Updated - - -

My PAL is interlaced but RGsB not interlaced
 

SunnySkyguy

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Maybe its not RGsB signal.

YCBCR?

maybe you could draw a block diagram.

show which sources are grounded and where interference is generated .

Perhaps cable has ferrite CM choke missing?
 

tanbakoo

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Thank you for your attention
It is RGsB and I made it through FPGA and ADV7125 and filtered with ADA4412 also it has common mode chock and ferrite on video and return line.my connector is triaxial and inner shield of cable connect to video return (it is not isolated from circuit GND but circuit GND was isolated from input power return [DC/DC isolated]) and outer shield connect to shield of box.
All of these condition equal for PAL and RGsB but PAL work good and RGsB does not work good.
 

tanbakoo

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when connect rgsb signal to a standard monitor (with green and gnd signal) when a noise occur monitor display go off and on again (TFT Controller start automatic detection of signal again) but when connect to my display (It is a fix resolution Display) it is have a line in display (Horizontal). It is show that my problem perhaps related to composite sync separation from video. but I do not know how to fix it?



I have a multilayer board that have solid ground plain under the part.

I have EMI filter and other part so my power rail is clean.

About ADA4412 first cutoff set to 18MHz and then set to 36MHz.both of them have same problem.
 

SunnySkyguy

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Maybe its not RGsB signal.

YCBCR?

maybe you could draw a block diagram.

show which sources are grounded and where interference is generated .

I would expect Sync on green, where a composite sync (CS) signal is overlaid on the wire used to transport the green signal.

If you see a thick horizontal line, then it is missing Vertical Sync. in the CS
 

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