How to locate the source of radiated noise from a power DTU?

Locating the source of DTU radiated noise requires a near-field probe and a spectrum analyzer. The near-field probe scans the PCB and cables to identify radiating hotspots. The spectrum analyzer is set to the corresponding frequency band, such as 30MHz-1GHz. Common noise sources include clock circuits, switching power supplies, and unfiltered interfaces. After location, targeted measures such as shielding, filtering, or layout optimization are taken. For example, a shield is added to the clock circuit, and a PBZ1608A-102Z0T ferrite bead is added to the switching power supply output. The effectiveness of the measures is verified by comparing the radiated field strength before and after the rectification. Precise location can quickly resolve radiation exceeding standards and reduce rectification time.