I may have an issue with conducted EMI through the ground connections between devices in a system. There is specifically a device which clearly creates noise on the measured signal from another circuit with a scope (noise is reduced when it's off). That scope has to be connected to both that noisy device and the measured circuit so I'm suspecting HF noise is conducted through the ground.
I am thinking about putting ferrite beads on the ground connections for example on the ground connection from all the devices (especially the noisy one) to the scope, but that layout looks like odd to me. Does it make sense to have a ferrite for the ground lead of a coaxial cable? Is there any other way?
Additionally, the scope is directly connected to the measured circuit, which is a resistor with one grounded lead (It's a current consumption measurement). Another approach I'm thinking about is a differential amplifier, does this approach looks better? Can even be necessary a combination of both?