HI farid, this is a very frequent asked question.....in the si-list... and i am sure some other one could also indicate you where have a look for a list of answer to your question. To calculate Z0 of a trasmission line one can use formula from text book for a first rough estimation in your case you should use formula for offset stripline another more precise approach is to use a field solver to calculate Zo and Xtalk coefficient matrix for a more accurate and useful results. ther are many field solver on the market you may want download Maxwell SV from Ansoft if you like .... Regards Giancarlo Guida HF & SI Application Engineer ANSOFT Corporation Piazzale Asia, 21 00144 Roma - Italy Phone +39-06-5916845 Fax +39-06-54222623 E-mail: gguida@xxxxxxxxxx Http://www.ansoft.com ----- Original Message ----- From: "farid syed" <farid_syed77@xxxxxxxxxxx> To: <si-list@xxxxxxxxxxxxx> Sent: Thursday, May 26, 2005 12:22 PM Subject: [SI-LIST] Calculating the Z0 of a trace Dear all, I am new to PCB design and i have a few doubts as listed below 1. I have a board with the stack up S G S S P G S S P S if i want to find the Z0 of a trace on the 4th layer then how do i do it? 2. is that type called a stripline, i have read that stipline is a trace bounded by ground planes on either side. and microstrip is the one with ground on one side and air on the other. what is the type of trace on the 4th layer of my board? 3. I have been through Dr. howard jhonson's handbook where crosstalk is calculated as = k/1+(d/h)^2 what is K and when we get a number as a result of the calculation how to use that number in determining the crosstalk or use it for our purpose. can anybody please help/guide me thanks in advance warm regards Fareed Yahoo! India Matrimony: Find your life partneronline. ------------------------------------------------------------------ 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