Interestingly, as I somewhat alluded to in my post on this topic, the development work that went into the CE limit was based on the original LISN design, which was a 5 uH model, whose impedance was specified from 150 kHz to 30 MHz, and based on impedance measurements on a DC-3 aircraft back in the 1940s. While that power type and distribution is entirely different than the power grid, that was available and that was what they used. It was only when they wrote the official limit and test procedure that they switched to the 50 uH LISN, so the LISN could be roughly 50 over the entire limit frequency range. The 5 uH LISN is 5 at 150 kHz, and doesn¹t get close to 50 until above 2 MHz.
Ken Javor Phone: (256) 650-5261 From: Brent DeWitt <bdew...@ix.netcom.com> Reply-To: Brent DeWitt <bdew...@ix.netcom.com> Date: Mon, 12 Aug 2019 17:21:45 -0400 To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Frequency range for conducted emissions For the upper end; conducted measurements end where radiated emissions start. Back in the mists of time someone decided that a ten meter wavelength was something that could radiated fairly efficiently from cables, so radiated emissions sounded like more of a risk to telecommunications. The 150 kHz number is more directly related to licensed services. The limit was 450 kHz in the US until harmonization with the European measurements. The US limit was based on protection of the AM broadcast band. The European Longwave AM band extends down to 148kHz, so I assume they simply rounded up to 150 kHz. >From a practical standpoint, if you stick with a 50 uH LISN, it starts to deviate from 50 ohms quite a bit as you go lower. Hope that helps. Respectfully, Brent DeWitt, AB1LF On 8/12/2019 4:36 PM, 000006cee064502d-dmarc-requ...@ieee.org wrote: > > > > > > > > Hello group, > > > > > Does anyone know why the conducted emissions for ITE products starts at 150KHz > and end at 30MHz? Why not start at 120KHz or 190KHz. Why finish at 30 and not > 40MHz? > > > > > Thank you > > Peter > > > > > > > > > > > > > > - > ---------------------------------------------------------------- > > > 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://www.ieee-pses.org/emc-pstc.html > > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used > formats), large files, etc. > > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > > For help, send mail to the list administrators: > Scott Douglas <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai gn=sig-email&utm_content=emailclient&utm_term=icon> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai gn=sig-email&utm_content=emailclient&utm_term=link> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> - ---------------------------------------------------------------- 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://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- 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://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
