How should the shield ground and coupling ground of a power line carrier PLC be handled?

The handling of shielding ground and coupling ground in power line carrier PLCs needs to be differentiated based on the shielding type and coupling method. The cable shield should be grounded at one end, typically at the receiving end, to avoid ground loops. For high-frequency shielding, a 360-degree termination method should be used, ensuring shielding continuity through metal clips or conductive pads. Coupling ground refers to the secondary ground of the signal coupling transformer and should be isolated from the primary ground, providing a high-frequency path through a capacitor (1nF) or resistor (1MΩ). On the PCB, the shielding ground is a separate area, connected to the digital ground via a PBZ1608A-102Z0T ferrite bead. For metal casings, the shielding ground is directly connected to the chassis ground. During testing, a shielding effectiveness testing system is used to verify the shielding effect; the shielding effectiveness should be greater than 60dB in the 30MHz-1GHz range. With proper handling, coupling noise can be reduced by more than 20dB, improving signal integrity.