In = Induced noise current Vn = noise voltage
Vn = In * Rs
Definition : A ground circuit allowing ground currents to flow in a loop causing two problems.
When noise voltage is induced due to magnetic coupling, the resulting induced current causes voltages in the signal.
The return current may take a path further away from the signal current and create a radiating loop.
Solution : Use a shielded cable and do not use the shield as a return conductor. (i. e. use either a twisted shielded pair or a tri axial cable.)