As high-performance motor car trains and electric/electronic devices have become more widespread in recent years, their influence on broadcasting/communications and the EMC (Electro Magnetic Compatibility) of electric/electronic systems has been frequently discussed. At the same time, an international standard for EMC in railways is being drawn up based on European standards (Table 1). Opinions or proposals are keenly expected concerning compatibility in Japan and the suitability of evaluation techniques.
      The Railway Technical Research Institute (RTRI) has therefore conducted a study into the measuring and evaluation methods of radio noise strength. The study showed that, after determining the electromagnetic ambient levels along electric railways and around rolling stock vehicles, the radio noise strength of vehicles with inverters tends to be stronger than that of conventional motor cars in a frequency range of several MHz (Fig. 1). The RTRI proposed a method which have been reflected in the draft of the EMC international standard for railways and also developed a measuring and evaluation support system (Fig. 2).
      Plans are underway to develop evaluation techniques for the influences of radio noise on digital transmission and the radio environment inside the vehicle.