I have to pass a couple of analog signals between separately grounded systems over a HPDB68 cable. Ground loops have been a major issue previously, so the signals are passed differentially and recovered against target ground using a differential amplifier. The shield is connected to ground on one side. On the other side, I'd connect it to the PCB ground using a capacitor to short RF but break LF loop.
What bothers me is: what is the common way to do it with the D-Sub connector on metal enclosure? Those connectors are usually screwed right on, which does not allow for the capacitor. Making custom spacer for isolation is doable, but this has to be a common issue? There have to be some off-the-shelf parts and solutions for this? Yet I can neither find nor remember ever seeing such an example?