In this circuit, the video signal is generated from the SoC through the ANALOG_OUT pin and routed through a filter stage before being delivered to the final output.

The image above represents the correct OSD output.

The image above shows OSD output exhibiting ghosting artifacts.

The video filter in use is described in the TPF140 datasheet, which I’ve also attached.
Does anyone have insight into the possible root cause of this issue or suggestions for how to debug it?
The goal is to reduce or eliminate the ghosting effect shown in the image.
I tried adding a 47µF series capacitor at the final output stage, and it seems to slightly reduce the ghosting, but I’m not entirely sure. Any help or guidance would be greatly appreciated.

thx.

 

The time that I saw, and solved, a similar ghosted VGA image, it was the result of using a poor quality connection cable. With a much better quality cable and no other difference, the ghosting was gone. That was a simple fix. Excessive capacitance to the shield over the video wire.

 

The time that I saw, and solved, a similar ghosted VGA image, it was the result of using a poor quality connection cable. With a much better quality cable and no other difference, the ghosting was gone. That was a simple fix. Excessive capacitance to the shield over the video wire.

Yes, the ghosting is excessive edge ringing that can be caused by mismatched impedance in the cable and/or load termination. I've seen people use random audio cable or 50 ohm coax cable on 75 ohm video networks