Conformity Magazine - July 2008 - (Page 23)

Future Developments The framework for the future structure of EMC standards is constantly being developed and, from the anechoic chamber perspective, this is no exception. Before we discuss the work of CISPR/I and the proposed CISPR 32 standard, we need to look at the work of a number of different joint task forces (JTFs) that have been formed by the CISPR/A and the IEC SC77B organizations. The three JTFs of interest to us are working on 3 different standards as follows: fully anechoic room (Draft IEC 61000-422) [16]; TEM cell (IEC 61000-4-21 [17]); and mode-stirred/ reverberation chamber (IEC 61000-4-20 [18]). While TEM cell and mode-stirred chamber standards are published and already going through maintenance updates, they define well known existing methods for these particular technologies and we will assume the reader is familiar with them. The draft FAR document however, “IEC 61000-4-22 Ed.1: Radiated emissions and immunity measurements in fully anechoic rooms (FARs),” will be published in the future. Its purpose is to address both radiated emissions and immunity measurements in a single document, and thus reduce measurement times without compromising the integrity of the either test. The reciprocity between radiated emissions and immunity measurements is underlined by the harmonization of the chamber validation method, validation criteria, required equipment, EUT setup requirements, and measurement/ scanning techniques wherever possible between emissions and immunity tests. This standard does not propose any limits for measurements performed in FARs, and does not require any new technology to be developed. Limits appropriate for the methods described in this standard will have to be defined by subcommittees responsible for product measurements, if they choose to adopt the methods defined in the new standard. Since only one calibration/validation procedure is performed, and a calibrated field probe or reference antenna is used as the traceable reference instrument for the entire test system, the expenditure of applying this standard for both emissions and immunity tests is believed to be less, compared to applying the separate emission and immunity requirements and procedures contained in the CISPR 16 standard series and IEC 61000-4-3 [19]. The validation method (Figure 11) is a volumetric test similar to that of the FAR method below 1GHz defined in CISPR 161-4, and measures the field strength and the forward power at each position to determine a system transducer factor at each point. The validation is carried out by either measuring with two antennas and a vector network analyzer system, or by using an antenna and field probe system. The average system transducer factor and the standard deviation (SdB) are calculated over all points for each polarization and compared to the acceptance criterion. Together, we can specify an effective EMI shielding solution for your application. Whether you’re shielding an entire cabinet or a handheld device, Chomerics has the right EMI solution for your application. When you need shielding for telecommunications, avionics, information systems, automotive, consumer, industrial or medical electronics – Chomerics has you covered. Chomerics EMI shielding products include: and compounds Partner with the leading global manufacturer of EMI shielding solutions – Chomerics. Now also offering Tecknit and Silver Cloud EMI products. www.chomerics.com 781.939.4850 chomailbox@parker.com JULy 2008 Conformity 23 http://www.chomerics.com http://www.chomerics.com

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Conformity Magazine - July 2008 Contents Editor's Note FCC Adopts 6 Million Dollars in DTV Enforcement Orders Commission Enforcement Bureau Adopts V-Chip Consent Decree FDA Seeks 2 Million Dollars from Medical Device Manufacturer FDA Answers Questions About CFLs and UV Radiation EPA Issues Energy Star Specs for TV, Video Boxes Canada Unveils Sweeping Product Safety Legislation How the Evolution of CISPR Standards Continues to Shape the Requirements for Anechoic Chambers ESD Open Forum Reach Compliance for Non-EU Article Manufacturers The iNARTE Informer Preamplifier Considerations for Emission Measurement Systems Effective Shielding in Medical Electronics Applications Product News Focus On...Power Components Buyer's Guide Updated Standards List for the EU's ATEX Directive EOS/ESD Symposium Set for September CPSC Actions in the News Researchers Work to Develop Non-Flammable Batteries Safety Link Launches Redesigned, Enhanced Web Site IEC Standards Update UL Standards Update Product Reviews Telcordia Standards Update From Our "You Can't Make This Stuff Up" Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - July 2008

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