On Tue, 13 Sep 2011 21:03:11 +0000, "Kunde, Brian" <brian_ku...@lecotc.com> wrote:
> I have received several very useful replies so far, but I have a > question. Since the limits for low frequency magnetic fields set out > by the ICNIRP is not flat across a frequency range, wouldn't the > measuring devices have to be able to provide not only the level but > also the frequency? For instance, if a device is generating high > magnetic fields at the 3rd harmonic of 50hz, do these meters have the > ability to distinguish frequency or do they just give the highest > reading such as a power meter? Several of the meters recommended so > far really don't make this clear on their datasheet. The ICNIRP guideline, and standards such as IEC 62233, specify how the magnetic field levels at each frequencies should be weighted and summed. In general, magnetic field exposure meters such as Narda ELT-400 (and Hioki 3470, Combinova MFM3000, and more?) have the weighting curve in it, and can display the result for the entier frequency range as a percentage to the selected reference level. If we only need to evaluate the exposure level against the reference level supported by the exposure meter, we don't have to know the frequency. If we also want to know the spectrum of the field, some exposure meter may have raw signal output or build-in spectrum display features. This kind of exposure meters are easy to use, but possible problem is that they can support only few known exposure standards in general and can become quite useless for reference levels not supported by the meter. Regards, Tom -- Tomonori Sato <vef00...@nifty.ne.jp> URL: http://homepage3.nifty.com/tsato/ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
