Improvement in the reproducibility of radiated emission measurements in a fully anechoic room by using VHF-LISN to control the termination condition of the AC mains cable leaving the EUT

摘要

In radiated emission measurements, the radiated disturbance from the AC mains cable leaving the equipment under test (EUT) significantly differs with the termination condition of the AC mains cable. Because this condition was not defined in applicable test standards, VCCI developed a device called the very high frequency line impedance stabilization network (VHF-LISN) that controls the termination impedance at the end of the power line in the test site connecting the AC mains cable of the EUT. Since then, VCCI has verified the effectiveness of VHF-LISN in the reproducibility of radiated emission measurements in semi anechoic chambers (SACs) while making proposals to CISPR, leading to discussions on the conditioning of the AC mains cable termination currently under way in CISPR SC-I/WG2. Now, VCCI has completed a new series of tests on the VHF-LISN in a fully anechoic room (FAR) according to the test method adopted in CISPR 32 Edition 2.0. This paper reports the results of these new tests and concludes that the reproducibility of radiated emission measurements in the FAR is also verified to improve significantly by controlling the termination condition of the AC mains cable through the use of VHF-LISN.