Ground loops affect video signals. Understand them, then deal with them. When designing or installing the cables for a video transmission system, one assumption that engineers commonly make is that the local earth grounds of both ends of the cable are the same. When circumstances don’t support this assumption, the video performance can exhibit gross distortions.
Solve ground loop problems in long-distance video transmission article looks at the situations in which ground may have a non-zero potential, and reviews the basic options for grounding connectivity. Finally, it shows a solution that ensures quality video transmission, even when any ground-potential differences are present. This article shows a common-mode compensation for differential transmission lines.