How to suppress radiation interference from concentrators?

The radiated interference from the concentrator mainly comes from the high-frequency switching power supply, digital clock circuit, and carrier communication circuit, typically in the 30MHz-1GHz frequency band. Suppression needs to address the source, path, and chassis shielding.

Source suppression: Add RC snubbers (e.g., 100pF + 10Ω) to the MOSFETs and diodes of the switching power supply to reduce dv/dt; use a low-jitter crystal oscillator in the clock circuit and mitigate edge interference through a series 22Ω resistor.

Path filtering: Add ferrite cores (e.g., PBZ1608E600Z0T) to all incoming and outgoing cables (power lines, communication lines), and wrap them 3-5 times.

Chassis shielding: Use a metal chassis with good conductivity and continuity, use electromagnetic sealing gaskets in gaps, and use honeycomb panels for ventilation holes. Modules with high internal noise (such as the power supply) can be fitted with local shielding covers.

PCB design should ensure a complete ground plane and route critical signal lines on inner layers. After optimization, the radiated emissions of the concentrator can be reduced by 15 dBμV/m in the 30-200MHz frequency band, meeting the EN 55032 Class B radiation limits.