What are the benefits of putting chip ferrite beads in series with both the DC supply line and the ground line where they enter a PCB? I've read that this type of configuration can provide a level of protection against ESD. Is this correct?
Is there any other reason (besides a possibly small level of ESD protection) that you'd want to put a ferrite bead in series with a PCB's negative supply line (I called this ground above)? Possibly to prevent the propagation of noise coupled to the negative supply line?
What about the usage of chip ferrite beads for signals rather than power? What kind of signals need to be filtered for EMI suppression, and how do I choose what kind of chip beads to use, besides matching the rated current, voltage and DC resistance to what I want? I'm especially confused about impedance rating(is this a case of the higher the better/more RF attenuation?). Would these chip beads negatively affect the actual signal?