Hello Grace, The article mentioned below was not allowed to be mailed see IEEE EMC 2001 article "CISPR22: 1997 Conducted Emission on Telecom Ports Products Pass/Fail depending on Test Method"
Regards, KEn _____ From: Hall, Ken Sent: Thursday, May 10, 2007 5:08 AM To: 'Grace Lin'; [email protected] Subject: RE: ISN for Conducted Emission in accordance to CISPR 22 Ed 5.2:2006 Hello Grace, This topic has been argued and discussed, multiple papers, in CISPR/I AND CISPR/G since the early 80's. The problem may be/is political. However, with a few countries voting against the LCL requirements they ended up in the standard because > 75% of the voting countries approved. We need to influence every countries voting membership to only vote positive if they understand the technical implications of a standard. Attached is a paper from IEEE EMC 2001. Regards, KEn _____ From: [email protected] [mailto:[email protected]] On Behalf Of Grace Lin Sent: Thursday, May 10, 2007 4:00 AM To: [email protected] Subject: Re: ISN for Conducted Emission in accordance to CISPR 22 Ed 5.2:2006 Hi Neven, Thank you for the detail comments. I suggest you write a paper to the IEEE International Symposium on EMC. There are many EMC experts attending this Symposium, including many equipment manufacturers, rule makers, and government agencies. The Symposium record is distributed worldwide and kept forever. This is a good way to get attention and make friends. Grace On 5/9/07, [email protected] <[email protected]> wrote: Be careful if you want to use ISN for Cinducted Emission or Immunity testing of Ethernet or any other high speed differential-pair interface. I just could not resist to reply, because of so poor specifications which allow the ISN to cause APPARENT failures, and can cost the industry millions to "fix" problems that do not exist. I tried to talk with a major vendor of these devices, offering help to make them actually appropriate for use with high-speed diff-pair interfaces ( e.g. Ethernet), but there appears to be absolutely no interest. It appears there is too much politics and marketing, as opposed to engineering, that dictates how these devices are constructed (and specified). The cost is paid by the industry who is then forced to follow the standards. I have worked on many cases where after a reported emission failure, measured using ISN, the clamp-method ( e.g. VOltage and Current Clamp method) resulted in very different and passing result. So here are some of my thoughts on this topic.They are mostly based on the use of CDN/ISN for Immunity, but they really equally apply to both SLCE and Immunity. • The most recent 6100-4-6 standard specifies the common-mode (CM) impedance Zcm (Table 3) at the EUT-port of the coupling device • It also specifies that the Common-to-Differential mode conversion (defined by Longitudinal Conversion Loss or LCL) of the CDN should be better than the conversion of a cable or the equipment connected to the cable, whichever conversion is lower, i.e. whichever LCL value is larger (Note in 6.2.1.2 <http://6.2.1.2/> ) • The standard recognizes that a given method and coupling device may not be appropriate for all types of devices under test, so it allows for alternate test methods. Specifically, in 6.2 it says: "If CDNs are not suitable or available, other injection methods can be used". • The note in 6.2.1.2 <http://6.2.1.2/> , regarding common to differential mode conversion, recognizes that the CDNs for multi-pair balanced lines (e.g. UTP) may not be suitable: "Often, clamp injection needs to be applied to multi-pair balanced cables, because suitable CDNs might not be available." * *What defines "suitable" can be the major limiting factor • Rules for selecting appropriate method are given in 7.1. The main deciding factor for selection of the method is (again): "are the CDNs suitable?", which could result in a subjective decision • Conversion can be a problem with the currently available CDN and can make it not-suitable for Ethernet lines • Relatively well designed RJ45/Ethernet devices can have between -40 dB and -46 dB conversion (2%-1% impedance balance) • Ethernet devices, as well as other high-speed devices that utilize balanced differential pairs, are very sensitive to CM-DM conversion • It is critical that the conversion characteristics of any coupling devices be at least the same if not better than the conversion by the well-designed signal lines used for the application • In practice, on multi-pair balanced cables where all wires are coupled (e.g. 8 wires of a CAT5 UTP), it is not easy to: – specify how to measure conversion – measure conversion – specify required levels of conversion • Lack of clear and appropriate method for measuring conversion can also be a problem with currently pending draft CISPR22 emission standard. • The problem lies in the fact that the CDN/ISN is inserted into an otherwise well-balanced line. The design of the CDN/ISN is not balanced (the standards lack realistic requirement and appropriate verification method) and it creates mode-conversion, which can create apparent CM emission and susceptibility. This condition does not resemble the realistic situation were the cable is fairly balanced and uninterrupted • Conversion by the CDN/ISN can be well beyond the conversion characteristics of the cable. The currently specified test method for measuring conversion (or LCL) is not appropriate for multi-pair interfaces. • Test equipment should not increase the conversion by introducing imbalance considerably higher than that of the cable. Conversion by the test equipment artificially increases the test levels beyond the characteristics of the measured device and intended cabling, causing apparent failures • Therefore, unless better CDN/ISN devices are constructed (and/or better-defined in the standards), I recommend methods using clamps (e.g. Voltage and Current Clamp method), which preserve integrity of the used cabling and allow testing in more realistic environment. The CM-impedance requirement that can be of some concern with the clamp-methods is not hard to meet, at least for 4-pair differential interfaces, but that is another topic. I hope it helps make your decision. Regards, Neven -------------- Original message ---------------------- From: < [email protected] <mailto:[email protected]> > > Hi, > this may be easier than you think (or wish). > To my knowledge there are only two manufacturers at the moment: Teseq > and Fischer. > > Regards, > Ari Honkala > > > On 5/8/07, wendy <[email protected] > wrote: > > Dear All, > > > > My company intends to purchase the above mentioned. Will > someone recommend any brand/model that compiles to the latest > requirements? > > > > Regards, > > Wendy Nya > > - > ---------------------------------------------------------------- This > message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. Website: http://www.ieee-pses.org/ <http://www.ieee-pses.org/> > > To post a message to the list, send your e-mail to > [email protected] > > 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 [email protected] Mike Cantwell > [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] David Heald: > [email protected] > > All emc-pstc postings are archived and searchable on the > web at: > > http://www.ieeecommunities.org/emc-pstc > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - > ---------------------------------------------------------------- This > message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to > [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html <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 [email protected] Mike Cantwell [email protected] > > > For policy questions, send mail to: > > Jim Bacher: [email protected] <mailto:[email protected]> David Heald: > [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > > http://www.ieeecommunities.org/emc-pstc > > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. Website: <http://www.ieee-pses.org/> http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > 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 [email protected] > Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] > David Heald: <mailto:[email protected]> [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html <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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: <http://www.ieeecommunities.org/emc-pstc> http://www.ieeecommunities.org/emc-pstc From: <[email protected]> To: < [email protected] <mailto:[email protected]> > List-Post: [email protected] Date: Tue, 8 May 2007 11:17:17 +0000 Subject: RE: ISN for Conducted Emission in accordance to CISPR 22 Ed 5.2:2006 Hi, this may be easier than you think (or wish). To my knowledge there are only two manufacturers at the moment: Teseq and Fischer. Regards, Ari Honkala On 5/8/07, wendy <[email protected] > wrote: Dear All, My company intends to purchase the above mentioned. Will someone recommend any brand/model that compiles to the latest requirements? Regards, Wendy Nya - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
