How to properly ground the cable shielding layer inside the edge computing box?

Improper grounding of the shielding layer of internal cables in edge computing boxes, such as LVDS display cables, antenna feeders, and USB extension cables, can introduce interference. Correct methods include:

1. The shielding layer should be grounded 360° at both ends, i.e., the connector metal shell and PCB ground are shorted through conductive foam or via large-area vias for return current. If a ground loop risk exists, a 1nF 2kV Y capacitor can be connected in series at one end to achieve high-frequency grounding and DC isolation.

2. The length of the shielding layer stripped should be less than 3mm to avoid the pigtail effect; otherwise, the shielding effectiveness will be reduced by 90%.

3. Use tinned copper braided mesh with a shielding rate >90%, and solder both ends to the PCB signal ground.

For high-frequency lines, it is recommended to use a common-mode ferrite ring (CMZ7060A-701T) from Etymotic to clip onto the cable end for common-mode suppression. Typical measurements show that grounding at both ends + ferrite ring can reduce radiated emissions from 30-300MHz by 20dB.