How to locate the noise source in the near field of the PAC EMC intelligent controller?

Locating EMC noise sources in a PAC (Power Controller Acoustic Control Unit) requires the use of near-field probes and a spectrum analyzer. Near-field probes are divided into electric field and magnetic field probes, used to scan PCBs, cables, and gaps. The probes are brought close to suspected noise sources (such as clock chips, power chips, and interfaces), and the amplitude changes of noise frequency points on the spectrum analyzer are observed.

Simultaneously, combined with far-field test results, the near-field hotspots corresponding to the exceeding frequency points are identified. For example, if 30MHz radiation exceeds the limit and near-field scanning reveals clock harmonics, targeted shielding or filtering can be added. After location, an oscilloscope can be used to analyze the noise time-domain waveform. This method can quickly locate noise sources, providing direction for rectification and improving EMC design efficiency.