I've a PCB radiating noise inside a metal enclosure (this is Product 1 from this question here). Unfortunately, I can't change the PCB itself, so I'm having to tackle the problem by other means. I can shield the metal enclosure to contain the noise, but I also need to deal with the cables exiting the enclosure. I've got a few questions regarding the best way to prevent the noise from coupling to the cables:
- Regarding the cable shields, is it best to connect the shield to ground at the point at which they connect to the PCB, or at the point at which they exit the enclosure?
- I'm guessing ferrites are best placed right at the point at which the cable exits the enclosure. Is this correct?
- Does it make much difference placing the ferrite on a shielded cable compared to an unshielded one?
- a. Is it best to place the ferrite before the cable shield starts, or after?