The conducted noise were measured in the frequency band for international standards suggested by CISPR (International Special Committee on Radio Interference), American FCC (Federal Communication Commission), MIL-STD (Military Standard), Japanese VCCI (Voluntary Control Council for Interference) and CE mark etc.
However, international specification about the radiation noise converted from conducted noise has not been established. In this thesis, the conducted noise was measured by applying a noise of EFT`s level 4, to transmission line which was defined by international standard IEC 61000-4-4. According to the experimental results, the noise radiated from the transmission line was observed in a frequency band broader than 30㎒ - 50㎒ band suggested by Military Standard, CISPR, and FCC.
From the transmission line, a radiation noise was observed from DC to 500 ㎒ in a short distance (from 5 to 45 ㎝) and also from DC to 400 ㎒ in a long distance of 1 m. From the above results, it is to be concluded that the international standards for a wider noise frequency band than the conventional ones should be established to consider the radiation noise converted from conducted noise.