Inter-laboratory Comparison Result as the Proficiency Testing Program of EMI Test Sites in Japan

Recently, the inter-laboratory comparison as the proficiency testing program based on the ISO/IEC Guide 43-1 was performed to the EMI test sites in Japan by VLAC (Voluntary EMC Laboratory Accreditation Center Inc.), the Japanese Accreditation Body for EMC test laboratories. A comb generator operated by AC mains was used for the artifact, since the technical proficiency of EMI measurement cannot be evaluated unless both of the conducted emission and the radiated emission data are measured among EMI test laboratories. This program, therefore, was performed to measure the conducted emission noise from the switching regulator incorporated to the power supply circuit of the artifact and to measure the radiated noise emitted from the comb generator itself through the enclosure and AC mains cable. For the radiated emission measurement, the artifact was connected through the VHF-LISN (VHF-line impedance stabilization network) to supply the AC mains. That is, the line to ground impedance of mains power supply was specified to all participated test sites for the radiated emission measurement. As the result of this program, the distribution width of a group formed with the collected data was kept from 6 dB to 10 dB, therefore it was easy to find the laboratory which had an isolated data from the group.