Well, it goes back at least to CISPR 22, Edition 2.0 (1993) which is the oldest version I have on my computer here at work (hard copy of Edition 1.0 at home). I was not involved in the writing of the standard at that time, so I can’t say what the understanding was then. And, I cannot speak for CISPR SC I WG3 on this matter as we haven’t discussed it in the years I’ve been a member of the working group.
That said, you will be interested to know that the current DRAFT Committee Draft for CISPR 32, the multimedia equipment emissions standard that ultimately is to replace CISPR 13 (Broadcast Receivers) and CISPR 22 (ITE) does provide a bit more guidance. In Annex C (Normative) the following is stated: “If the level of an isolated emission exceeds the limits, it shall be ignored provided the following two conditions are met when measured over a two minute interval: 1. The emission does not exceed the limit for more than 1 second, and 2. The emission does not exceed the limit more than once in any 15 second observation period.” This looks to me to be an enhancement on the wording in CISPR 22 and does not conflict with it. Your choice, but this is something I wouldn’t hesitate to hang my hat on. Hope this helps. Ghery S. Pettit Member, CISPR SC I WG2 (writing CISPR 32) Convener, CISPR SC I WG3 (maintaining CISPR 22 and 24) From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Pickard, Ron Sent: Wednesday, February 11, 2009 8:36 AM To: rehel...@mmm.com Cc: emc-p...@ieee.org Subject: RE: Brief and Isolated And more importantly, why should it be ignored, especially if it’s coming >from the EUT? This term is a remnant from at least CISPR 22:1997. We should all have an understanding of the descriptor “brief isolated”, but we do not know the applicable defined conditions of this subjective term (cyclic, random, single occurrence, how high is high, how brief is brief, how isolated is isolated, etc?) or the mindset of the standard writers when it was first introduced. If not defined in the standard or specifically referenced to somewhere else and due its subjective nature, “brief isolated” is certainly left to interpretation. Comments? Maybe the CISPR 22 standards writers could interject. Best regards, Ron Pickard ron.pick...@intermec.com <mailto:ron.pick...@intermec.com> From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of rehel...@mmm.com Sent: Wednesday, February 11, 2009 10:07 AM To: emc-p...@ieee.org Subject: Brief and Isolated In Clause 6.1 of EN55022:2006 A1:2007 it states: "The EUT shall meet the limits of Table 5 or Table 6 when measured at the measuring distance R in accordance with the methods described in Clause 10. If the reading on the measuring receiver shows fluctuations close to the limit, the reading shall be observed for at least 15 s at each measurement frequency; the highest reading shall be recorded, with the exception of any brief isolated high reading, which shall be ignored." Does anyone know what "brief isolated" could mean or am I left to my own to devices to define it as I see fit? Bob Heller 3M EMC Laboratory, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 - 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.ieeecommunities.org/emc-pstc 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...@ptcnh.net> 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.ieeecommunities.org/emc-pstc 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...@ptcnh.net> 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.ieeecommunities.org/emc-pstc 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...@ptcnh.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com>
