If you combined a tool like FlowEMC with a tool like SpecctraQuest or Hyperlynx, with a logic simulator that allowed you to exercise the board/system in a fully functional manner, so that the simulated ibis devices were triggering at the right timing intervals and sending their voltages/currents down the simulated tracks with the simulated planes/shapes and sucking up and sourcing current through the simulated power delivery system, in the simulated housing/shelf/frame with the attached I/O and power cables, you could in theory get some reasonably accurate emissions profiles for your board/housing/shelf/system if direct emissions from the chip packages were ignored. You would also need massive memory and cpu capacity. I apologize for the run on sentence. By properly using SI tools, EMC tools, and your experience, you can design to minimize EMI and EMC susceptibility as well as quickly troubleshoot for EMI/EMC failures. Every design is a balance between meeting functionality/specs and cost. The design tools let you understand and evaluate the compromises so that you can meet your design requirements at the minimum cost ($, space, weight, power, ...). Cheers, -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Chris Cheng Sent: Friday, December 03, 2004 2:13 AM To: 'Charles Grasso '; Chris Cheng; 'zhang_kun@xxxxxxxxxx '; 'si-list@xxxxxxxxxxxxx ' Subject: [SI-LIST] Re: EMI simulation tools at PCB level You mean the =22 part ? :-D Seriously, I know it is understandable and explainable but I want it to be automatically predicted and simulated by a tool. It is easy to fix and patch after the fact but I have yet to see a tool to tell me ahead of time the db and peaks location. A bare PCB with a few "experimental traces" as in some EMI papers, sure. A multi-boards system with chassis and spaghetti cables come out ? Show me the money. -----Original Message----- From: Charles Grasso To: Chris.Cheng@xxxxxxxxxxxx; zhang_kun@xxxxxxxxxx; si-list@xxxxxxxxxxxxx Sent: 12/2/2004 10:31 PM Subject: RE: [SI-LIST] Re: EMI simulation tools at PCB level Chris - It would be *much* easier for you to contact some experienced EMC engineers - the phenomena you describe are understandabe and explainable. -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Chris Cheng Sent: Thursday, December 02, 2004 5:13 PM To: 'zhang_kun@xxxxxxxxxx'; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: EMI simulation tools at PCB level I am sure the consumer product guys will laugh at my stupidity but I can never design a PCB that will pass FCC B without a large metal cage chassis. I've always wanted to simulate why if I tighten the screw by one more turn on my door and my EMI gaskets compressed a little harder and the signature changed by 10 db. Or if I hang the cable this way or that way the signature changed by a few db. What I am trying to say is while EMI from PCB may be the source, the enclosure/environment the PCB is in seems to have a bigger impact on whether you are passing FCC than the PCB itself. Granted this is just from an incompetent designer like me who cannot ship an absolute clean PCB that can be wrapped in a plastic bag and passing FCC. Any simulation tools that can help me ? ps Is there any way I can receive messages from the list from outside the US without these =2 =22 ? I know the US or English language is not the center of the Universe so I appolgize in advanced. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu