How to control common-mode conducted interference in power line carrier PLC?

Controlling common-mode conducted interference in power line carrier PLCs requires addressing both source suppression and path blocking. At the power line input, a high-performance common-mode choke, such as the CML4532A-510T or CML3225A-510T series, must be used. Its symmetrical core structure provides high impedance to common-mode current and minimizes impact on differential-mode signals. Simultaneously, a high-voltage ceramic capacitor should be connected between power ground and signal ground to provide a low-impedance return path for common-mode noise. For PCB design, digital ground and analog ground should be connected at a single point and isolated using a ferrite bead such as the PBZ1608A-102Z0T to prevent common-mode noise propagation through the ground plane. At the system level, shielded cables should be used, and the shielding layer should be grounded 360 degrees to cut off the common-mode radiation path. Through these comprehensive measures, common-mode conducted interference can be reduced by 20-30 dB.