Conducted Emission testing for Ethernet over power line product.
Hi Group, I am looking for an opinion regarding an interpretation and implementation of CISPR I/89/CD. Let's say you have a product that can transmit Ethernet over power lines in your house (this is not power over Ethernet). This could be considered as Power Line Communication with Multi Purpose Port (AC main + data). If we would have followed old CISPR22 methodology for testing conducted emission, while Ethernet is transmitting, it would've fail (just to make sure, it did fail) at 5Mhz-30Mhz range. So IEC recognized the problem and come up with some amendments to CISPR22 and I believe it is still a life document. It is my understanding, that based on those amendments, for PLC product, Cond. Emis. has to be tested in 2 ways: 1)old way with LISN, data Tx is off, regular CE AC limits; 2)with Tx on, with TISN, against Telecomm limits. Is my understanding correct? If yes, is there TISN for 240V and if there someone out there, who actually did this test already? Thank you, Mark Gandler - 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 emc-p...@ieee.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: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Are there any knowm EMC porblems when transmitting video on gigabite ethernet?
It is just Ethernet traffic, so there should be no difference in emission. Immunity might be a problem, since during some tests (e.g. EFT), temporary loss of packets and link-drop will most likely happen. That is not an issue with regular data-only Ethernet applications, since Ethernet normally checks for errors and re-transmits if packets have been lost, but real-time applications might suffer. It could disturb video if there is not enough safety-margin in the code that allows for the lost packets to re-transmit without disturbances (as defined by the manufacturer AND EN55024 section on LAN). I do not know enough about the application, but check for that. That can happen e.g. with IP phones, where link-drop results in a call-drop, which is then a test failure (it requires user-intervention to redial, so the Ethernet self-correction does not work). Neven -- Original message -- > Hi everyone > > Does any member know of any known EMC problems associated with transmitting > video over a gigabite ethernet system? > > Regards > Andy > > ___ > > Andrew Price > Principal Hardware Engineer (EMC Specialist) > > SELEX Sensors and Airborne Systems > Christopher Martin Road > Basildon > Essex > SS14 3EL > Mail ref: A125 > > Tel: +44 (0) 1268 883308 > email: andrew.p.pr...@selex-sas.com > > > > > This email and any attachments are confidential to the intended > recipient and may also be privileged. If you are not the intende! d > recipient please delete it from your system and notify the sender. > You should not copy it or use it for any purpose nor disclose or > distribute its contents to any other person. > > > - > > 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 emc-p...@ieee.org > > Instructions: http://listserv.ieee.org/listserv/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: emc-pst c...@daveheald.com > > 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Are there any knowm EMC porblems when transmitting video on gigabite ethernet?
Hi everyone Does any member know of any known EMC problems associated with transmitting video over a gigabite ethernet system? Regards Andy ___ Andrew Price Principal Hardware Engineer (EMC Specialist) SELEX Sensors and Airborne Systems Christopher Martin Road Basildon Essex SS14 3EL Mail ref: A125 Tel: +44 (0) 1268 883308 email: andrew.p.pr...@selex-sas.com This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: neutral fusing
Chris, I do not believe that this kind of fusing is permitted if the fuses are "user accessible". But as I remember from my previous life, fusing of neutral is permitted in Class I equipment if a suitable warning (for example "double pole/neutral fusing") is provided to a service person. John Radomski Schneider Automation "James, Chris" To: Sent by: cc: emc-p...@ieee.orgSubject: neutral fusing 11/24/2005 04:12 AM Does EN60065 permit fusing in both line and neutral? Regards, Chris - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Suppression of radiated emissions and spread spectrum clocking
This is a multi-part message in MIME format.
Isn't it fun, that's why I am not sure if being called an EMC expert is a good
thing.
Now to the point:
1) Pulling back the Vcc plane away from the edge of the "ground" plane changes
the distribution of the EM field at the edge. While the strength at the edge
decreases, it can indeed increase radiation in another direction. There have
been papers published on that, e.g. search for Gisin and Tanner in the IEEE
EMC Symposia or Transactions records. However, what is the practical
application and usefulness? While the radiation pattern is changed, one should
notice that on the typical PCBs none of the mechanisms of radiations
("edge-fringing" or Patch-antenna) are not efficient radiators, and in my
experience the direct radiation off the PCB edge or off the (undercut) Vcc
plane is typically not a problem, because Vcc planes are typically at an
electrically very small distance to the "ground" planes (even in a not-so-good
PCB stackup), and the field falls-off quickly with the distance from the edge
of the Vcc plane (wherever it is! ). Also, in many cases, the Vcc planes are
in between other plane ("ground") layers, which again changes the field
distribution and coupling and radiation mechanisms (there is no patch-antenna
in the PCB if it is sandwitched in the inner layers).
The typical practical problem with the edge-radiation that I have seen is not
the direct radiation, rather it is when the PCB-edge is close to a piece of
metal that is electrically larger, e.g. card-cage in a chassis. The field at
the edge in that case feeds the larger antenna (piece of metal), which then
radiates as a secondary-radiator much more efficiently. Another similar
situation is in the areas of the PCB-moats. The Vcc that is extended all the
way to the "ground" plane edge (of the moat) can very efficiently couple the
EM field into the moat, which then easily guides it and couples to the I/O
across the moat, e.g. a transformer. In such a case, the transformer and/or
common-mode choke across the moat do not suppress the common-mode energy
coupled to them.
The papers I have seen only concentrate on the redirection of energy, but fail
to recognize that the real practical issue is typycally not the direct
radiation but the secondary radiation.
I'd say, the expert who is stating that it is uselles is definitelly wrong -
sometimes it is very benefitial as described above (and witnessed in extensive
practice). It is also true that sometimes it does not matter. The expert who
said it CAN definitely help is right - it depends on the circumstances.
It is typically easy to pull the Vcc planes back and stitch the “ground”
planes together at the edges, which eliminates the issue with emission coming
>from secondary radiators - so why not do it? However, the energy is still
going somewhere inside the PCB stackup, so the signal routing, PCB-stackup,
bypassing etc. can/should/must be used to minimize the levels and the coupling
with the PCB structures that can radiate or carry it to the I/O sections.
2) Spread-spectrum is frequency modulation of the clock signal. If one looks
in any textbook on the topic (or remembers from the school), in FM the
side-bands receive power from the carrier, so that the deeper the modulation
is the power (hence the amplitude) of the carrier is lower and the power (the
amplitude) of the side-bands is higher – the total power in the signal is
constant. The ideal SS technique, from the point of view of minimizing the
radiated emission maximum amplitude) is such that the level at the carrier
frequency and the level at the sidebands are equal. Any deeper modulation and
the sidebands are higher than in the equilibrium, and any lower modulation and
the carrier is higher (thus they are not optimal). Also, the waveform of the
modulating signal can make large difference, check Lexmark web page on that.
I'd say the expert was wrong on the second one. Again - see the math of how FM
works.
Cheers, Neven
Conformity and SI List
I attended an electronic conference where a well-known EMI/EMC speaker/author
stated that the 20 H rule is useless for suppression of radiated emissions.
On the other hand, another well known EMI/EMC speaker/author states that it
can definitely help. What is the opinion of conformity (SI) members and what
empirical results have been obtained?
Second question. A well-known EMI speaker/author also states that spread
spectrum clocking (SSC) does not lower peak radiated emissions. Rather the
harmonics of SSC are spread out where the Quasi Peak Detector Spectrum
Analyzer (QPDSA) is missing (incorrect frequency band) their peak value
readings, i.e. fpeak is outside the frequency band that SPDSA is set for
monitoring.
Thanks.
Robert Hanson
- This
message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. Website: ht
2006 IEEE EMC Portland Symposium: EMC Technical Committee 8 Prod uct Safety Workshop - Call for Workshop Papers
Greetings All, The 2006 IEEE EMC Symposium is being held in Portland, Oregon, from August 14 to 18, 2006. Technical Committee 8 (TC-8, Product Safety as it relates to EMC) has sponsored the TC-8 Product Safety Workshop (TC-8 PSW) for the past several years at the EMC symposiums. To continue the tradition of supporting the EMC symposiums, TC-8 invites those who wish to participate in the product safety workshop to submit a proposal for consideration. Proposals should be submitted via email to the TC-8 Chair, Richard Georgerian, mailto:richa...@ieee.org, Tel.: 303-218-5748. Workshop presentations proposals should contain the following: 1. Presentation title 2. Author(s) with full contact information, including name, address, telephone number, and e-mail address. 3. Description of the presentation, including abstract, summary and format. 4. Presentations are expected to be 45 minutes in length. If more time is required, please advise at your earliest. 5. For presentations that include live demonstrations, please advise of any special considerations that may be needed. For planning and scheduling purposes, please send in proposals by January 15, 2006. Sincerely, Richard Georgerian TC-8 Chair = Compliance Engineer Carrier Access Corporation 5395 Pearl Parkway Boulder, CO 80301 U.S.A. Tele: 303-218-5748 Fax: 303-218-5503 mailto:rgeorger...@carrieraccess.com - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Suppression of radiated emissions and spread spectrum clocking
Cortland, The Ansoft URL's pdf comes up nil. Going to the \thewave\ index doesn't list that .pdf Would you send me a copy? - Robert - On Sun, 27 Nov 2005 20:47:48 -0500 Cortland Richmond <72146@compuserve.com> wrote: > Ken Javor wrote > > >> I didn't know what the 20 H rule was either, just > assumed everyone else > did... << > > See > http://www.qsl.net/wb6tpu/si-list4/0391.html > page 9 of > http://www.ansoft.com/thewave/Shielding_and_Decoupling.pdf > http://factaee.elfak.ni.ac.yu/fu2k12/fu04.html > and others (search on "20H rule.") > > RF between two equally sized planes does radiate from the > slot formed at > the edge - but RF on a small plane over a larger one also > radiates from the > slot around the smaller. We don't want to put patch > antennas on a board > while trying to avoid other problems. Thus the > controversy. > > > > Cortland > KA5S > - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: WEEE labelling in the UK
So what are you doing about product you are selling in MS who already have legislation? Historic waste is everything pre 13 Aug 2005 - you can't have different dates throughout the MS. If you apply the wheelie without the bar but have the date marked on the unit you cover all bases. Bottom line it's your decision, your legal fees, your product market - everyone else is doing what the letter asks, or rather I have seen no other dissenters on several other WEEE/RoHS forums - if you go to a compliance scheme that's what they'll say you should be doing. Regards, Chris From: Colgan, Christopher [Harman Pro Group UK] [mailto:christopher.col...@harmanpro.com] Sent: 25 November 2005 17:00 To: James, Chris; Emc-Pstc (E-mail) Subject: RE: WEEE labelling in the UK But that's my point. All the guidelines etc state something like "The Government proposes to implement on 13 August 2005 the WEEE Directive" but they haven't. The draft Statutory Instrument hasn't even been completed, let alone laid before parliament. Without an SI, there's no legislation, ergo, there's no enforcement. My concern is that we will mark products before legislation requires us to do so. This may confuse the historical waste issue if the SI declares a date other than August 13. I don't think you can have retrospective legislation. ie how can you have a law that state "all products will be marked from last year"? The UK Government are in breach of the directive and they're in trouble with Brussels. In the meantime the poor manufacturers are being told to prepare for WEEE legislation but not being told exactly what the WEEE legislation is! Cheers Chris _ Christopher Colgan Compliance Engineer Soundcraft & Studer Harman International Industries Ltd Tel: +44 (0) 1707 668081 Fax: +44 (0) 1707 660755 EMail: christopher.col...@harmanpro.com Web : http://www.soundcraft.com Web : http://www.studer.ch This email may contain confidential / privileged information and is intended, solely for the use of the named recipient(s). If you are not the intended recipient you may not disclose, copy, distribute or retain any part of this message or attachments. If you have received this e-mail in error please notify the sender immediately via e-mail. Any views or opinions expressed are solely those of the author and do not necessarily represent those of Harman International Industries Ltd or its affiliated companies. -Original Message- From: James, Chris [mailto:c...@dolby.co.uk] Sent: 25 November 2005 16:43 To: Colgan, Christopher [Harman Pro Group UK]; Emc-Pstc (E-mail) Subject: RE: WEEE labelling in the UK Chris - see topmost bullet point on page 2 of this: http://www.dti.gov.uk/sustainability/weee/Planning_for_Implementation.pd f Marking still required from the 13th Aug 2005 Regards, Chris This message (including any attachments) may contain confidential information intended for a specific individual and purpose. If you are not the intended recipient, delete this message. If you are not the intended recipient, disclosing, copying, distributing, or taking any action based on this message is strictly prohibited. - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: WEEE labelling in the UK
Chris - see topmost bullet point on page 2 of this: http://www.dti.gov.uk/sustainability/weee/Planning_for_Implementation.pd f Marking still required from the 13th Aug 2005 Regards, Chris From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Colgan, Christopher [Harman Pro Group UK] Sent: 25 November 2005 16:14 To: Emc-Pstc (E-mail) Subject: WEEE labelling in the UK Hello All Would anyone care to confirm (or otherwise) that as the WEEE directive has not yet been transposed into UK law, that the "wheelie bin" logo is not required to be applied to products sold in the UK? I've researched numerous websites, including the out of date and rather unhelpful DTi's site, and found nothing concrete. August 13 2005 keeps being mentioned but surely if there's no legislation, this is nonsense? Here's to a good weekend. Regards Chris Colgan _ Christopher Colgan Compliance Engineer Soundcraft & Studer Harman International Industries Ltd Tel: +44 (0) 1707 668081 Fax: +44 (0) 1707 660755 EMail: christopher.col...@harmanpro.com Web : http://www.soundcraft.com Web : http://www.studer.ch This email may contain confidential / privileged information and is intended, solely for the use of the named recipient(s). If you are not the intended recipient you may not disclose, copy, distribute or retain any part of this message or attachments. If you have received this e-mail in error please notify the sender immediately via e-mail. Any views or opinions expressed are solely those of the author and do not necessarily represent those of Harman International Industries Ltd or its affiliated companies. - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message (including any attachments) may contain confidential information intended for a specific individual and purpose. If you are not the intended recipient, delete this message. If you are not the intended recipient, disclosing, copying, distributing, or taking any action based on this message is strictly prohibited. - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: WEEE labelling in the UK
Chris - sorry to disappoint but that was one of the things you still had to do. it is in Chris Tollady's letter on the dti site if I recall - I'll take a look... Regards, Chris From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Colgan, Christopher [Harman Pro Group UK] Sent: 25 November 2005 16:14 To: Emc-Pstc (E-mail) Subject: WEEE labelling in the UK Hello All Would anyone care to confirm (or otherwise) that as the WEEE directive has not yet been transposed into UK law, that the "wheelie bin" logo is not required to be applied to products sold in the UK? I've researched numerous websites, including the out of date and rather unhelpful DTi's site, and found nothing concrete. August 13 2005 keeps being mentioned but surely if there's no legislation, this is nonsense? Here's to a good weekend. Regards Chris Colgan _ Christopher Colgan Compliance Engineer Soundcraft & Studer Harman International Industries Ltd Tel: +44 (0) 1707 668081 Fax: +44 (0) 1707 660755 EMail: christopher.col...@harmanpro.com Web : http://www.soundcraft.com Web : http://www.studer.ch This email may contain confidential / privileged information and is intended, solely for the use of the named recipient(s). If you are not the intended recipient you may not disclose, copy, distribute or retain any part of this message or attachments. If you have received this e-mail in error please notify the sender immediately via e-mail. Any views or opinions expressed are solely those of the author and do not necessarily represent those of Harman International Industries Ltd or its affiliated companies. - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message (including any attachments) may contain confidential information intended for a specific individual and purpose. If you are not the intended recipient, delete this message. If you are not the intended recipient, disclosing, copying, distributing, or taking any action based on this message is strictly prohibited. - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Suppression of radiated emissions and spread spectrum clocking
Thank you, now that I understand that 20 H means the power plane outside edge is set back from the ground plane edge a distance 20 times the separation between the two planes, it is possible to opine on the subject. Looking at the fringing field set up by potentials and gradients between the two planes, if you follow the 20 H rule the radiation efficiency will be much less, the quasi-static and induction fields will be there, but much less of the energy will break off and radiated as a traveling electromagnetic wave. > From: Cortland Richmond <72146@compuserve.com> > Date: Sun, 27 Nov 2005 20:47:48 -0500 > To: ieee pstc list > Subject: Re: Suppression of radiated emissions and spread spectrum clocking > > Ken Javor wrote > >>> I didn't know what the 20 H rule was either, just assumed everyone else > did... << > > See > http://www.qsl.net/wb6tpu/si-list4/0391.html > page 9 of http://www.ansoft.com/thewave/Shielding_and_Decoupling.pdf > http://factaee.elfak.ni.ac.yu/fu2k12/fu04.html > and others (search on "20H rule.") > > RF between two equally sized planes does radiate from the slot formed at > the edge - but RF on a small plane over a larger one also radiates from the > slot around the smaller. We don't want to put patch antennas on a board > while trying to avoid other problems. Thus the controversy. > > > > Cortland > KA5S > > - > > 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 emc-p...@ieee.org > > Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com > > 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Suppression of radiated emissions and spread spectrum clocking
Ken Javor wrote >> I didn't know what the 20 H rule was either, just assumed everyone else did... << See http://www.qsl.net/wb6tpu/si-list4/0391.html page 9 of http://www.ansoft.com/thewave/Shielding_and_Decoupling.pdf http://factaee.elfak.ni.ac.yu/fu2k12/fu04.html and others (search on "20H rule.") RF between two equally sized planes does radiate from the slot formed at the edge - but RF on a small plane over a larger one also radiates from the slot around the smaller. We don't want to put patch antennas on a board while trying to avoid other problems. Thus the controversy. Cortland KA5S - 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 emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
