Re: Conducted noise emission diagnosis device
I read in !emc-pstc that Ken Javor ken.ja...@emccompliance.com wrote (in b8855fd1.e9f%ken.ja...@emccompliance.com) about 'Conducted noise emission diagnosis device', on Tue, 5 Feb 2002: Later he built and patented its sibling, a cmrn. I suppose I shouldn't REALLY be surprised that one can patent a balun again in the USA. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Conducted noise emission diagnosis device
I read in !emc-pstc that John Woodgate j...@jmwa.demon.co.uk wrote (in ke$8bqa3m8x8e...@jmwa.demon.co.uk) about 'Conducted noise emission diagnosis device', on Tue, 5 Feb 2002: If C is the common-mode (CM) component and D is the differential-mode (DM) component (both in linear units, not decibels), then one output of the LISN gives C + D and the other gives C - D. This follows from the definitions of CM and DM. Correction. The outputs are 2(C+D) and 2(C-D). -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Conducted noise emission diagnosis device
Hi Mat, The book is: Introduction to Electromagnetic Compatibility Author: Clayton R. Paul The copy that I have is copywrite 1992, John Wiley Sons. There is a whole bunch of library of congress data...in the front cover. I'm not sure what is helpful, except for maybe the ISBN which is, 0-471-54927-4 Chris -Original Message- From: Aschenberg, Mat [SMTP:matt.aschenb...@echostar.com] Sent: Tuesday, February 05, 2002 9:33 AM To: Chris Maxwell; mur...@eel.ufsc.br Cc: EMC-PSTC Internet Forum Subject: RE: Conducted noise emission diagnosis device What is that title of the Clayton Paul book? -Original Message- From: Chris Maxwell [SMTP:chris.maxw...@nettest.com] Sent: Tuesday, February 05, 2002 6:16 AM To: mur...@eel.ufsc.br Cc: EMC-PSTC Internet Forum Subject:RE: Conducted noise emission diagnosis device Hi Muriel, After I read your reply. I got a little scared. I actually forgot how I did it. (It has been a few years.) I too have a commercial LISN that has a switched output. It won't work with the separator. I had to actually walk over to the lab and pick through the cobwebs to figure out what was missing. The BIG detail that I forgot to tell you was that I built a prototype of the LISN that is in Clayton Paul's book as well. This LISN has the phase and neutral emissions brought out to separate outputs, not switched. So, in order to take the measurements, I had to use this LISN and the separator. Both were built for less than $100 in parts. And as you can see, both haven't been used for quite a while. The LISN was built before I got into safety design, so I leave it on the shelf and use the nice safe one that we purchased. When I get the time, I'll share some of the components... off line. For now, it would be helpful to refer to the LISN schematic in Clayton R. Paul's book. That will answer the question of how a single LISN could work. Sorry for the confusion. Chris -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@eel.ufsc.br] Sent: Tuesday, February 05, 2002 9:02 AM To: Chris Maxwell Subject: RE: Conducted noise emission diagnosis device Hi Chris, I have a LISN (RohdeSchwarz) that have changing from Neutral/Phase by a switch. Most separators from common-mode and differential mode use 2 LISN's to obtain their noise currents separated. Is there a way of building this separator with my type of LISN? And, if it's not asking too much, do you have or know any schematic with construtive details of a separator? Thanks for the help! Regards, Muriel -- Original Message -- From: Chris Maxwell chris.maxw...@nettest.com Date: Tue, 5 Feb 2002 07:43:43 -0500 Hi Muriel, I have the same book by Clayton Paul as it was used as a textbook for a graduate course in EMC at SUNY Binghamton. After SUNY Binghamton, I started was working as a design engineer. That was the year before the EMC directive became mandatory. My boss saw Mr Paul's book in my office... and well...next thing you know, I'm suddenly the EMC guy with Captain Zap for a nickname... Enough about my sad fall from grace :-) One of the first things I did was to build one of these devices. I never have seen one for sale. Honestly, until your email, I thought I was the only person who actually tried to make one. (other than Mr. Paul himself) I don't use it too much any more. We have gotten fairly good at guessing whether the emission is differential mode or common mode. If we guess correctly, it's quicker to just put in the capacitor or choke and give it a try. It's been a while since I built it, so my memory is fuzzy. But I may be able to help if you have a question or two. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@eel.ufsc.br] Sent: Monday, February 04, 2002 10:38 PM To:EMC-PSTC Subject: Conducted noise emission diagnosis device Hello Group, I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode
RE: Conducted noise emission diagnosis device
What is that title of the Clayton Paul book? -Original Message- From: Chris Maxwell [SMTP:chris.maxw...@nettest.com] Sent: Tuesday, February 05, 2002 6:16 AM To: mur...@eel.ufsc.br Cc: EMC-PSTC Internet Forum Subject: RE: Conducted noise emission diagnosis device Hi Muriel, After I read your reply. I got a little scared. I actually forgot how I did it. (It has been a few years.) I too have a commercial LISN that has a switched output. It won't work with the separator. I had to actually walk over to the lab and pick through the cobwebs to figure out what was missing. The BIG detail that I forgot to tell you was that I built a prototype of the LISN that is in Clayton Paul's book as well. This LISN has the phase and neutral emissions brought out to separate outputs, not switched. So, in order to take the measurements, I had to use this LISN and the separator. Both were built for less than $100 in parts. And as you can see, both haven't been used for quite a while. The LISN was built before I got into safety design, so I leave it on the shelf and use the nice safe one that we purchased. When I get the time, I'll share some of the components... off line. For now, it would be helpful to refer to the LISN schematic in Clayton R. Paul's book. That will answer the question of how a single LISN could work. Sorry for the confusion. Chris -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@eel.ufsc.br] Sent: Tuesday, February 05, 2002 9:02 AM To: Chris Maxwell Subject:RE: Conducted noise emission diagnosis device Hi Chris, I have a LISN (RohdeSchwarz) that have changing from Neutral/Phase by a switch. Most separators from common-mode and differential mode use 2 LISN's to obtain their noise currents separated. Is there a way of building this separator with my type of LISN? And, if it's not asking too much, do you have or know any schematic with construtive details of a separator? Thanks for the help! Regards, Muriel -- Original Message -- From: Chris Maxwell chris.maxw...@nettest.com Date: Tue, 5 Feb 2002 07:43:43 -0500 Hi Muriel, I have the same book by Clayton Paul as it was used as a textbook for a graduate course in EMC at SUNY Binghamton. After SUNY Binghamton, I started was working as a design engineer. That was the year before the EMC directive became mandatory. My boss saw Mr Paul's book in my office... and well...next thing you know, I'm suddenly the EMC guy with Captain Zap for a nickname... Enough about my sad fall from grace :-) One of the first things I did was to build one of these devices. I never have seen one for sale. Honestly, until your email, I thought I was the only person who actually tried to make one. (other than Mr. Paul himself) I don't use it too much any more. We have gotten fairly good at guessing whether the emission is differential mode or common mode. If we guess correctly, it's quicker to just put in the capacitor or choke and give it a try. It's been a while since I built it, so my memory is fuzzy. But I may be able to help if you have a question or two. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From:Muriel Bittencourt de Liz [SMTP:mur...@eel.ufsc.br] Sent:Monday, February 04, 2002 10:38 PM To: EMC-PSTC Subject: Conducted noise emission diagnosis device Hello Group, I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode and differential mode noise current are measured by LISN and the LISN can't tell which mode is the dominant current. I came across a paper by Clayton Paul and Keith Hardin which explain the usefulness of a separator like this that would identified the dominant current from the total current. Hence, the correct capacitor value(either X-caps or Y-caps) can be changed accordingly so to reduce the overall conducted noise. The book by Clayton Paul Introduction to Eletromagnetic Compatibility has also mention about this device. I have contacted a few persons trying to look for the person who have actually built this separator himself and I am also looking for any vendor
Re: Conducted noise emission diagnosis device
Dear Muriel, The Differential- or Common-mode Box design is in the IEEE Transactions on EMC, Vol. 30, No.4, November 1988, pages 553-560. Figure 2 shows the schematic and Figure 3 has an inside picture. The box is very easy to make. It is made from two transformers, two resistors, and a switch. The picture has enough detail that one can see that it matches the schematic. The VARI-L transformer LF428 may have to be back ordered and you have to buy a minimum of 5 parts. We still use the one in the picture. If you do not want to make your own, Pointsix is a company that has made some in the past. You could try them at www.pointsix.com. I have a call into them to see if they still make it. They are based here in Lexington, Kentucky. I'll let you know what I find out. Please let me know if you have any more questions. Regards, Keith Hardin Senior Technical Staff Member Lexmark International Inc. Muriel Bittencourt de Liz muriel%eel.ufsc...@interlock.lexmark.com on 02/04/2002 10:37:35 PM Please respond to Muriel Bittencourt de Liz muriel%eel.ufsc...@interlock.lexmark.com To: EMC-PSTC emc-pstc%ieee@interlock.lexmark.com cc:(bcc: Keith Hardin/Lex/Lexmark) Subject: Conducted noise emission diagnosis device Hello Group, I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode and differential mode noise current are measured by LISN and the LISN can't tell which mode is the dominant current. I came across a paper by Clayton Paul and Keith Hardin which explain the usefulness of a separator like this that would identified the dominant current from the total current. Hence, the correct capacitor value(either X-caps or Y-caps) can be changed accordingly so to reduce the overall conducted noise. The book by Clayton Paul Introduction to Eletromagnetic Compatibility has also mention about this device. I have contacted a few persons trying to look for the person who have actually built this separator himself and I am also looking for any vendor who have this product for sale. So far, my effort has yield no results. Can anybody point me to the right person so that i can try to built this separator myself. Any other suggestion and comments are greatly appreciated. Best Regards, ** Muriel Bittencourt de Liz Ph.D. Student Federal University at Santa Catarina Florianópolis, SC Brazil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Conducted noise emission diagnosis device
Hi, A very descriptive device is presented in the following book: Power Line Filter Design for Switched Mode Power Supplies. By Mark Nave. It is out of print, and if you see a copy for sale, it's worth buying. He also took out a patent for his device under the following no: US Patent No: 4,849,685 Dated Jul 18, 1989. If you want a more detailed description I recommend you buy a copy from the US Patent office. 3 US Dollars for an internet download. Not free, but cheap enough to make it worth buying the PDF version. His device basically cancels out the DM noise, then you design a filter for the CM noise. Fit the CM filter, and remove the device, then measure again and the difference will mostly be the DM noise making it easier to design the filter. Simple really and from the looks of the design cheap!( the parts you probably have laying around in your workshop!) I keep meaning to make one but have yet to get around it. Oh yes, symmetry is important and you will need a LISN with two outputs. Enci At 00:37 05/02/02 -0300, you wrote: Hello Group, I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode and differential mode noise current are measured by LISN and the LISN can't tell which mode is the dominant current. I came across a paper by Clayton Paul and Keith Hardin which explain the usefulness of a separator like this that would identified the dominant current from the total current. Hence, the correct capacitor value(either X-caps or Y-caps) can be changed accordingly so to reduce the overall conducted noise. The book by Clayton Paul Introduction to Eletromagnetic Compatibility has also mention about this device. I have contacted a few persons trying to look for the person who have actually built this separator himself and I am also looking for any vendor who have this product for sale. So far, my effort has yield no results. Can anybody point me to the right person so that i can try to built this separator myself. Any other suggestion and comments are greatly appreciated. Best Regards, ** Muriel Bittencourt de Liz Ph.D. Student Federal University at Santa Catarina Florianópolis, SC Brazil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Conducted noise emission diagnosis device
Hi Muriel, After I read your reply. I got a little scared. I actually forgot how I did it. (It has been a few years.) I too have a commercial LISN that has a switched output. It won't work with the separator. I had to actually walk over to the lab and pick through the cobwebs to figure out what was missing. The BIG detail that I forgot to tell you was that I built a prototype of the LISN that is in Clayton Paul's book as well. This LISN has the phase and neutral emissions brought out to separate outputs, not switched. So, in order to take the measurements, I had to use this LISN and the separator. Both were built for less than $100 in parts. And as you can see, both haven't been used for quite a while. The LISN was built before I got into safety design, so I leave it on the shelf and use the nice safe one that we purchased. When I get the time, I'll share some of the components... off line. For now, it would be helpful to refer to the LISN schematic in Clayton R. Paul's book. That will answer the question of how a single LISN could work. Sorry for the confusion. Chris -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@eel.ufsc.br] Sent: Tuesday, February 05, 2002 9:02 AM To: Chris Maxwell Subject: RE: Conducted noise emission diagnosis device Hi Chris, I have a LISN (RohdeSchwarz) that have changing from Neutral/Phase by a switch. Most separators from common-mode and differential mode use 2 LISN's to obtain their noise currents separated. Is there a way of building this separator with my type of LISN? And, if it's not asking too much, do you have or know any schematic with construtive details of a separator? Thanks for the help! Regards, Muriel -- Original Message -- From: Chris Maxwell chris.maxw...@nettest.com Date: Tue, 5 Feb 2002 07:43:43 -0500 Hi Muriel, I have the same book by Clayton Paul as it was used as a textbook for a graduate course in EMC at SUNY Binghamton. After SUNY Binghamton, I started was working as a design engineer. That was the year before the EMC directive became mandatory. My boss saw Mr Paul's book in my office... and well...next thing you know, I'm suddenly the EMC guy with Captain Zap for a nickname... Enough about my sad fall from grace :-) One of the first things I did was to build one of these devices. I never have seen one for sale. Honestly, until your email, I thought I was the only person who actually tried to make one. (other than Mr. Paul himself) I don't use it too much any more. We have gotten fairly good at guessing whether the emission is differential mode or common mode. If we guess correctly, it's quicker to just put in the capacitor or choke and give it a try. It's been a while since I built it, so my memory is fuzzy. But I may be able to help if you have a question or two. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@eel.ufsc.br] Sent: Monday, February 04, 2002 10:38 PM To:EMC-PSTC Subject: Conducted noise emission diagnosis device Hello Group, I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode and differential mode noise current are measured by LISN and the LISN can't tell which mode is the dominant current. I came across a paper by Clayton Paul and Keith Hardin which explain the usefulness of a separator like this that would identified the dominant current from the total current. Hence, the correct capacitor value(either X-caps or Y-caps) can be changed accordingly so to reduce the overall conducted noise. The book by Clayton Paul Introduction to Eletromagnetic Compatibility has also mention about this device. I have contacted a few persons trying to look for the person who have actually built this separator himself and I am also looking for any vendor who have this product for sale. So far, my effort has yield no results. Can anybody point me to the right person so that i can try to built this separator myself. Any other suggestion and comments are greatly appreciated. Best Regards, ** Muriel Bittencourt de Liz Ph.D. Student Federal University at Santa Catarina Florianópolis, SC
RE: Conducted noise emission diagnosis device
Hi Muriel, I have the same book by Clayton Paul as it was used as a textbook for a graduate course in EMC at SUNY Binghamton. After SUNY Binghamton, I started was working as a design engineer. That was the year before the EMC directive became mandatory. My boss saw Mr Paul's book in my office... and well...next thing you know, I'm suddenly the EMC guy with Captain Zap for a nickname... Enough about my sad fall from grace :-) One of the first things I did was to build one of these devices. I never have seen one for sale. Honestly, until your email, I thought I was the only person who actually tried to make one. (other than Mr. Paul himself) I don't use it too much any more. We have gotten fairly good at guessing whether the emission is differential mode or common mode. If we guess correctly, it's quicker to just put in the capacitor or choke and give it a try. It's been a while since I built it, so my memory is fuzzy. But I may be able to help if you have a question or two. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@eel.ufsc.br] Sent: Monday, February 04, 2002 10:38 PM To: EMC-PSTC Subject: Conducted noise emission diagnosis device Hello Group, I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode and differential mode noise current are measured by LISN and the LISN can't tell which mode is the dominant current. I came across a paper by Clayton Paul and Keith Hardin which explain the usefulness of a separator like this that would identified the dominant current from the total current. Hence, the correct capacitor value(either X-caps or Y-caps) can be changed accordingly so to reduce the overall conducted noise. The book by Clayton Paul Introduction to Eletromagnetic Compatibility has also mention about this device. I have contacted a few persons trying to look for the person who have actually built this separator himself and I am also looking for any vendor who have this product for sale. So far, my effort has yield no results. Can anybody point me to the right person so that i can try to built this separator myself. Any other suggestion and comments are greatly appreciated. Best Regards, ** Muriel Bittencourt de Liz Ph.D. Student Federal University at Santa Catarina Florianópolis, SC Brazil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Conducted noise emission diagnosis device
I read in !emc-pstc that Muriel Bittencourt de Liz mur...@eel.ufsc.br wrote (in 017b01c1adf6$74216430$55ddbfc8@marx) about 'Conducted noise emission diagnosis device', on Tue, 5 Feb 2002: I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode and differential mode noise current are measured by LISN and the LISN can't tell which mode is the dominant current. If you are referring to the CISPR16-1 LISNs, it is true that they don't separate the common- and differential-mode currents, ***but you can**. If C is the common-mode (CM) component and D is the differential-mode (DM) component (both in linear units, not decibels), then one output of the LISN gives C + D and the other gives C - D. This follows from the definitions of CM and DM. This approach is suitable for wide-band measurements using an r.f. voltmeter or narrow-band measurements using a receiver, but for measurements with a spectrum analyser you need to derive the sum and difference voltages in real time, using a balun transformer, as described in the Armstrong-Williams article in 'EMC and Compliance Journal Issue 34. **Note that the diagram Figure 12 does not show the essential earth/ground connection to the enclosure.*** -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Conducted noise emission diagnosis device
Dear Muriel Separating CM from DM at the output of a LISN was covered by Michel Mardiguian and Joel Raimbourg in a paper they presented at the IEEE EMC Symposium held in Seattle in August 1999, titled: An alternate, complementary method for characterising EMI filters (Volume 2 of the Symposium Record, pages 882-886). They describe using a 'CM/DM splitter transformer' which is available from AEMC, a French company about whom I have no further details. But it does not seem difficult to make your own 'splitter' transformer as it appears to be a simple type of transformer. I referred to this paper and redrew their figure for the transformer in the article I wrote with Tim Williams for the EMC + Compliance Journal, April 2001, titled: EMC Testing Part 2 -Conducted emissions (pages 22 - 32, available on-line in their Archive section at www.compliance-club.com). Regards, Keith Armstrong www.cherryclough.com In a message dated 05/02/02 02:44:29 GMT Standard Time, mur...@eel.ufsc.br writes: Subj:Conducted noise emission diagnosis device Date:05/02/02 02:44:29 GMT Standard Time From:mur...@eel.ufsc.br (Muriel Bittencourt de Liz) Sender:owner-emc-p...@majordomo.ieee.org Reply-to: A HREF=mailto:mur...@eel.ufsc.br;mur...@eel.ufsc.br/A (Muriel Bittencourt de Liz) To:emc-p...@ieee.org (EMC-PSTC) Hello Group, I am looking for a device that will differentiate the dominant component (either common-mode or differential-mode current) in the total conducted noise emission current of a product measuring through its' power cord using a LISN. This device can be called common/differential mode current separator. In conducted noise emission measurement, both common-mode and differential mode noise current are measured by LISN and the LISN can't tell which mode is the dominant current. I came across a paper by Clayton Paul and Keith Hardin which explain the usefulness of a separator like this that would identified the dominant current from the total current. Hence, the correct capacitor value(either X-caps or Y-caps) can be changed accordingly so to reduce the overall conducted noise. The book by Clayton Paul Introduction to Eletromagnetic Compatibility has also mention about this device. I have contacted a few persons trying to look for the person who have actually built this separator himself and I am also looking for any vendor who have this product for sale. So far, my effort has yield no results. Can anybody point me to the right person so that i can try to built this separator myself. Any other suggestion and comments are greatly appreciated. Best Regards, ** Muriel Bittencourt de Liz Ph.D. Student Federal University at Santa Catarina Florianópolis, SC Brazil
