Improvement of radiated emission measurement reproducibility with VHF-LISN obtained from final results of international inter-laboratory comparison on termination control of power line

At present, power supply impedance of radiated emission measurement site is not specified in any testing standards. In measurement of radiated emission from desktop equipment, noise emitted from power line of the EUT is a factor that worsens site correlations because the noise varies with the impedance between power line and the ground. Under such circumstances, VCCI developed VHF-LISN to stabilize power supply facilities for the purpose of improving the reproducibility of radiated emission measurement. To assess its effectiveness, an international inter-laboratory comparison program was carried out, provided with EUTs and termination control devices including the VHF-LISN to ensure identical setup across sites. Until February 2014, this international program was promoted at 16 sites in 9 countries. From the final results, we conclude that the VHF-LISN is the best device to improve the reproducibility of radiated emission measurement.