 a cali- good deal of agreement not only in methods of measurement but brated attenuation characteristic. The limit levels shown in Figure also in the limits themselves. The principal standards are sum- 23.19 have been normalised to a measurement distance of 10m for marized in Tables 23.5 and 23.6, and a comparison of the emission ease of comparison; different standards call up distances of 3m, 10m limits is shown in Figure 23.18 for conducted and Figure 23.19 for or 30m. A direct translation of the levels (according to 1/d) from radiated emission. Measuring equipment is defined in CISPR pub- 10m to 3m is not strictly accurate because of the influence of near lication 16, which is aligned with BS727. field effects. Note that there are detailed differences in the methods of meas- urement allowed between the various emission standards. Measure- ments on conducted emissions below 30MHz are made on the mains 23.10.2.2 Immunity standards terminals and use an artificial mains network, or Line Impedance Stabilising Network (LISN), to define the impedance of the mains Since immunity standards are of more recent development they supply. Radiated measurements above 30MHz require the use of an have not been adopted in the same way as emission standards. IEC 23/14 Safety and EMC EN Class A FCC Class A EN Class B FCC Class B 10kHz 100kHz 450kHz 10MHz 30MHz 150kHz 500kHz 1.6MHz Frequency Figure 23.18 Conducted emission limits (CISPR16 quasi-peak detector, 509/50uH LISN) Publication 801, aligned with BS6667, was published initially in In order to fill this gap, CENELEC have given a high priority to 1984 and refers specifically to requirements for industrial process developing the Generic Standards. These are standards with a wide control instrumentation, but it includes methods of assessment application, not related to any particular product or product family, which can be applied to a much wider range of products and forms and are intended to represent the essential requirements of the the basis for the CENELEC generic immunit