RE: RF immunity 1-2GHz
Hi Ken, Group, As I present courses on EMC in the Netherlands, I have this demo-box with me. It consists of a welded rust free steel box with a clamp tightened cover. The joints have EMC fingers in perfect state. For miscellaneous experiments 5 6 mm (0.2") holes are drilled in it. When I teach them about shielding I put my cellular in the box and ask one of the guys to call it. Great Surprise: it rings. Now I close all holes but one. It rings. Then I close the last one. It stops. The Dutch GSM provider sends at 1800 Mhz. If I considered a 10th of a wavelength for shielding, then I could allow for 16 mm. I have adjusted my lessons since then to adjust for this experiment and tell them that shielding only starts at 1/20th of a wave length. This was especially fun when I had these guys of Phoenix and other enclosure manufacturers in my Class. They are selling those 6 feet high 19"wide process controller enclosures to the industry having as "EMC cabinets" but they do not have a bottom in it to allow for cables to run. (they provide an earth rail, though) Regards, Gert Gremmen, (Ing) ce-test, qualified testing === Web presence http://www.cetest.nl CE-shop http://www.cetest.nl/ce_shop.htm /-/ Compliance testing is our core business /-/ === >>-Original Message- >>From: owner-emc-p...@majordomo.ieee.org >>[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Ken Javor >>Sent: Thursday, January 10, 2002 9:41 PM >>To: am...@westin-emission.no; emc-p...@majordomo.ieee.org >>Subject: Re: RF immunity 1-2GHz >> >> >> >>I have a little different experience than the other respondents >>to date, who >>pretty much said no extrapolation is possible from one band to another. >> >>My experience and analytical training tell me that if field intensity and >>modulation are held constant, then above 1 GHz coupling to wires running >>between equipments will decrease with increasing frequency. If the >>circuitry interfacing the equipments is slow with respect to 1 GHz, and it >>passed below 1 GHz, I would also expect it to pass above 1 GHz. >> >>If however the modulation scheme changes or the wires picking up the rf >>energy are electrically short just below 1 GHz, then the immunity could >>decrease with increasing frequency. >> >>A final consideration is how rf tight the equipment enclosure is. >> A rule of >>thumb of rf enclosure design is that slots and apertures should >>be held to a >>tenth wavelength long for good EMI performance. At 1 GHz, a tenth >>wavelength is 3 cm. It is likely that as frequency increases above 1 GHz >>that imperfections in equipment enclosure homogeneity will impact >>shielding >>effectiveness. >> >>Ken Javor >> >> >> >> >> >> on 1/10/02 6:06 AM, am...@westin-emission.no at am...@westin-emission.no >>wrote: >> >>> >>> RF immunity testing in the frequency range 80-1000MHz has been >>common in EU >>> for several years. Now, new standards also include testing in the 1-2GHz >>> band (3V/M or 10V/m, 1kHz sine, 80% AM) >>> >>> We have done a lot of testing in the 80-1000MHz band and quite often the >>> EUTs failed. We have also done some testing in the 1-2GHz band, >>but never >>> managed to disturb the EUTs in that manner so it fails (10V/m). >>> >>> What is your experience with RF immunity testing in 1-2GHz band >>? Do the EUT >>> fail? >>> >>> On one specific product we have tested 80-1000MHz (no failure) >>and emission >>> testing 30-1000MHz (almost quiet, 20 dB margin). >>> With these two tests performed, is it possible to assume that >>we will pass >>> the immunity 1-2GHz test ? >>> The answer might be, test it and verify, but we would like to argue that >>> this test is not necessary to conduct, because to our previous >>experience >>> with RF immunity. Many of your might not like this approach . so be >>> aware, this is just a question. >>> >>> Best regards >>> Amund Westin, Oslo/Norway >>> >>> >>> >>> >>> >>> --- >>> 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: >>> unsubsc
RE: RF immunity 1-2GHz
I'd like to add a few comments about paths and victim circuits. The externally applied RF field may have more than one path into the EUT. Let's assume you have just two paths; one via a powerline that's equipped with a modest filter, and another that is a radiated path through ventilation slots. The first path may allow energy between 30 MHz and 100 MHz to get to the EUT circuitry, but becomes a very lossy path above 100 MHz. The second path is very lossy below 2 GHz, but allows everything above that to get through. If you only tested for immunity up to 1 GHz, you would never know the second path existed. Any predictions about immunity performance of the entire EUT at 3 GHz would be misleading, since they would have been based only on observations of the performance of the first path. Now let's consider the victim circuitry. The electronics of the EUT are actually a large collection of tiny "victims", each with its own unique level of upset. If your EUT withstands everything up to 1 GHz without malfunction, that's still no guaranty that some collection of circuit traces and components will not have a resonance at 1.8 GHz, creating an upset condition. My point is that you can make decent predictions only if you know all the paths and all the victims. I have found that most real devices are so complex that performance predictions are wildly inaccurate. Rigorous testing is the only way to be sure. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis >-Original Message- >From: Ken Javor [mailto:ken.ja...@emccompliance.com] >Sent: Thursday, January 10, 2002 12:41 PM >To: am...@westin-emission.no; emc-p...@majordomo.ieee.org >Subject: Re: RF immunity 1-2GHz > > > >I have a little different experience than the other >respondents to date, who >pretty much said no extrapolation is possible from one band to another. > >My experience and analytical training tell me that if field >intensity and >modulation are held constant, then above 1 GHz coupling to >wires running >between equipments will decrease with increasing frequency. If the >circuitry interfacing the equipments is slow with respect to 1 >GHz, and it >passed below 1 GHz, I would also expect it to pass above 1 GHz. > >If however the modulation scheme changes or the wires picking up the rf >energy are electrically short just below 1 GHz, then the immunity could >decrease with increasing frequency. > >A final consideration is how rf tight the equipment enclosure >is. A rule of >thumb of rf enclosure design is that slots and apertures >should be held to a >tenth wavelength long for good EMI performance. At 1 GHz, a tenth >wavelength is 3 cm. It is likely that as frequency increases >above 1 GHz >that imperfections in equipment enclosure homogeneity will >impact shielding >effectiveness. > >Ken Javor > > > > > > on 1/10/02 6:06 AM, am...@westin-emission.no at >am...@westin-emission.no >wrote: > >> >> RF immunity testing in the frequency range 80-1000MHz has >been common in EU >> for several years. Now, new standards also include testing >in the 1-2GHz >> band (3V/M or 10V/m, 1kHz sine, 80% AM) >> >> We have done a lot of testing in the 80-1000MHz band and >quite often the >> EUTs failed. We have also done some testing in the 1-2GHz >band, but never >> managed to disturb the EUTs in that manner so it fails (10V/m). >> >> What is your experience with RF immunity testing in 1-2GHz >band ? Do the EUT >> fail? >> >> On one specific product we have tested 80-1000MHz (no >failure) and emission >> testing 30-1000MHz (almost quiet, 20 dB margin). >> With these two tests performed, is it possible to assume >that we will pass >> the immunity 1-2GHz test ? >> The answer might be, test it and verify, but we would like >to argue that >> this test is not necessary to conduct, because to our >previous experience >> with RF immunity. Many of your might not like this approach >. so be >> aware, this is just a question. >> >> Best regards >> Amund Westin, Oslo/Norway --- 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...@ga
Re: RF immunity 1-2GHz
I have a little different experience than the other respondents to date, who pretty much said no extrapolation is possible from one band to another. My experience and analytical training tell me that if field intensity and modulation are held constant, then above 1 GHz coupling to wires running between equipments will decrease with increasing frequency. If the circuitry interfacing the equipments is slow with respect to 1 GHz, and it passed below 1 GHz, I would also expect it to pass above 1 GHz. If however the modulation scheme changes or the wires picking up the rf energy are electrically short just below 1 GHz, then the immunity could decrease with increasing frequency. A final consideration is how rf tight the equipment enclosure is. A rule of thumb of rf enclosure design is that slots and apertures should be held to a tenth wavelength long for good EMI performance. At 1 GHz, a tenth wavelength is 3 cm. It is likely that as frequency increases above 1 GHz that imperfections in equipment enclosure homogeneity will impact shielding effectiveness. Ken Javor on 1/10/02 6:06 AM, am...@westin-emission.no at am...@westin-emission.no wrote: > > RF immunity testing in the frequency range 80-1000MHz has been common in EU > for several years. Now, new standards also include testing in the 1-2GHz > band (3V/M or 10V/m, 1kHz sine, 80% AM) > > We have done a lot of testing in the 80-1000MHz band and quite often the > EUTs failed. We have also done some testing in the 1-2GHz band, but never > managed to disturb the EUTs in that manner so it fails (10V/m). > > What is your experience with RF immunity testing in 1-2GHz band ? Do the EUT > fail? > > On one specific product we have tested 80-1000MHz (no failure) and emission > testing 30-1000MHz (almost quiet, 20 dB margin). > With these two tests performed, is it possible to assume that we will pass > the immunity 1-2GHz test ? > The answer might be, test it and verify, but we would like to argue that > this test is not necessary to conduct, because to our previous experience > with RF immunity. Many of your might not like this approach . so be > aware, this is just a question. > > Best regards > Amund Westin, Oslo/Norway > > > > > > --- > 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: RF immunity 1-2GHz
I have to agree with Peter - just because it passes in one band doesn't mean it will pass in another. For argument's sake in one instance, consider the loop area of a signal and it's return - it's effective at specific frequencies/frequency bands. Also consider why the new standard(s) added the higher frequency range - perhaps there were reports of/or concerns that products compliant at 800-1000 are now failing when in proximity to products emitting in the 1-2GHz range. Can't see the argument against testing. John Juhasz Fiber Options Bohemia, NY -Original Message- From: FLOWERDEW, Peter [mailto:peter.flower...@plantronics.com] Sent: Thursday, January 10, 2002 10:07 AM To: emc-p...@majordomo.ieee.org Subject: RE: RF immunity 1-2GHz I have been 'hardening' headsets and amplifiers to meet the 80 to 1000MHz, 1KHz 80% AM modulation requirements in EN55024, 3V/m. As our product lives on peoples desks we undertook to also provide immunity to mobile phones. We covered 900MHz, 1.8GHZ, 1.9GHz and 2.45GHz switched key modulation at 200Hz 1/8 pulse ratio, 10V/m to 3V/m. These higher frequency tests were MUCH more difficult to meet than the regulatory ones. The response of a system to signals in any particular frequency band just can not normally be predicted from the response to those in some other frequency band. Regards, Peter -Original Message- From: am...@westin-emission.no [ mailto:am...@westin-emission.no <mailto:am...@westin-emission.no> ] Sent: Thursday, January 10, 2002 11:07 AM To: emc-p...@majordomo.ieee.org Subject: RF immunity 1-2GHz RF immunity testing in the frequency range 80-1000MHz has been common in EU for several years. Now, new standards also include testing in the 1-2GHz band (3V/M or 10V/m, 1kHz sine, 80% AM) We have done a lot of testing in the 80-1000MHz band and quite often the EUTs failed. We have also done some testing in the 1-2GHz band, but never managed to disturb the EUTs in that manner so it fails (10V/m). What is your experience with RF immunity testing in 1-2GHz band ? Do the EUT fail? On one specific product we have tested 80-1000MHz (no failure) and emission testing 30-1000MHz (almost quiet, 20 dB margin). With these two tests performed, is it possible to assume that we will pass the immunity 1-2GHz test ? The answer might be, test it and verify, but we would like to argue that this test is not necessary to conduct, because to our previous experience with RF immunity. Many of your might not like this approach . so be aware, this is just a question. Best regards Amund Westin, Oslo/Norway --- 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/ <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: RF immunity 1-2GHz
Try putting a mobile phone next to your computer mouse! Even more fun if the computer has speakers! Peter -Original Message- From: ari.honk...@nokia.com [mailto:ari.honk...@nokia.com] Sent: Thursday, January 10, 2002 1:23 PM To: am...@westin-emission.no Cc: emc-p...@majordomo.ieee.org Subject: RE: RF immunity 1-2GHz Hi, today I heard about a case where an ISDN terminal was susceptible to a DECT phone next to it while a 900 MHz GSM did not cause anything. This was in the field, not in test lab. In test lab my experience is that if it passes below 1 G it does it also above it. However, as the 1.4-2 GHz sweep takes very short time we haven't bothered with this, just testing to avoid guessing. regards Ari Honkala > -Original Message- > From: ext [mailto:am...@westin-emission.no] > Sent: 10 January, 2002 13:07 > To: emc-p...@majordomo.ieee.org > Subject: RF immunity 1-2GHz > > > > RF immunity testing in the frequency range 80-1000MHz has > been common in EU > for several years. Now, new standards also include testing in > the 1-2GHz > band (3V/M or 10V/m, 1kHz sine, 80% AM) > > We have done a lot of testing in the 80-1000MHz band and > quite often the > EUTs failed. We have also done some testing in the 1-2GHz > band, but never > managed to disturb the EUTs in that manner so it fails (10V/m). > > What is your experience with RF immunity testing in 1-2GHz > band ? Do the EUT > fail? > > On one specific product we have tested 80-1000MHz (no > failure) and emission > testing 30-1000MHz (almost quiet, 20 dB margin). > With these two tests performed, is it possible to assume that > we will pass > the immunity 1-2GHz test ? > The answer might be, test it and verify, but we would like to > argue that > this test is not necessary to conduct, because to our > previous experience > with RF immunity. Many of your might not like this approach > . so be > aware, this is just a question. > > Best regards > Amund Westin, Oslo/Norway > > > > > > --- > 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: RF immunity 1-2GHz
I have been 'hardening' headsets and amplifiers to meet the 80 to 1000MHz, 1KHz 80% AM modulation requirements in EN55024, 3V/m. As our product lives on peoples desks we undertook to also provide immunity to mobile phones. We covered 900MHz, 1.8GHZ, 1.9GHz and 2.45GHz switched key modulation at 200Hz 1/8 pulse ratio, 10V/m to 3V/m. These higher frequency tests were MUCH more difficult to meet than the regulatory ones. The response of a system to signals in any particular frequency band just can not normally be predicted from the response to those in some other frequency band. Regards, Peter -Original Message- From: am...@westin-emission.no [mailto:am...@westin-emission.no] Sent: Thursday, January 10, 2002 11:07 AM To: emc-p...@majordomo.ieee.org Subject: RF immunity 1-2GHz RF immunity testing in the frequency range 80-1000MHz has been common in EU for several years. Now, new standards also include testing in the 1-2GHz band (3V/M or 10V/m, 1kHz sine, 80% AM) We have done a lot of testing in the 80-1000MHz band and quite often the EUTs failed. We have also done some testing in the 1-2GHz band, but never managed to disturb the EUTs in that manner so it fails (10V/m). What is your experience with RF immunity testing in 1-2GHz band ? Do the EUT fail? On one specific product we have tested 80-1000MHz (no failure) and emission testing 30-1000MHz (almost quiet, 20 dB margin). With these two tests performed, is it possible to assume that we will pass the immunity 1-2GHz test ? The answer might be, test it and verify, but we would like to argue that this test is not necessary to conduct, because to our previous experience with RF immunity. Many of your might not like this approach . so be aware, this is just a question. Best regards Amund Westin, Oslo/Norway --- 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: RF immunity 1-2GHz
Hi, today I heard about a case where an ISDN terminal was susceptible to a DECT phone next to it while a 900 MHz GSM did not cause anything. This was in the field, not in test lab. In test lab my experience is that if it passes below 1 G it does it also above it. However, as the 1.4-2 GHz sweep takes very short time we haven't bothered with this, just testing to avoid guessing. regards Ari Honkala > -Original Message- > From: ext [mailto:am...@westin-emission.no] > Sent: 10 January, 2002 13:07 > To: emc-p...@majordomo.ieee.org > Subject: RF immunity 1-2GHz > > > > RF immunity testing in the frequency range 80-1000MHz has > been common in EU > for several years. Now, new standards also include testing in > the 1-2GHz > band (3V/M or 10V/m, 1kHz sine, 80% AM) > > We have done a lot of testing in the 80-1000MHz band and > quite often the > EUTs failed. We have also done some testing in the 1-2GHz > band, but never > managed to disturb the EUTs in that manner so it fails (10V/m). > > What is your experience with RF immunity testing in 1-2GHz > band ? Do the EUT > fail? > > On one specific product we have tested 80-1000MHz (no > failure) and emission > testing 30-1000MHz (almost quiet, 20 dB margin). > With these two tests performed, is it possible to assume that > we will pass > the immunity 1-2GHz test ? > The answer might be, test it and verify, but we would like to > argue that > this test is not necessary to conduct, because to our > previous experience > with RF immunity. Many of your might not like this approach > . so be > aware, this is just a question. > > Best regards > Amund Westin, Oslo/Norway > > > > > > --- > 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.
