Avigdor Given the CI requirements currently being imposed, it is imperative that the impedance be measure either on the board or on a coupon from the same production panel. It is also very cost effective to design the CI traces and dielectric thicknesses using a field solver. Blindly using tables without knowing the underlying assumptions is comparative to landing an airplane blindfolded and without instruments. Best regards Lee J. Lee Parker, Ph.D. JLP Consultants LLC 804 779 3389 ----- Original Message ----- From: "Avigdor JAkubinsky" <[log in to unmask]> To: <[log in to unmask]> Sent: Monday, December 03, 2007 2:08 PM Subject: [TN] Calculated Impedance vs. CI with coupon Hello friends, It is always the question of controlling (CI) with Coupon measurement on the stack. Would any of you The Experts trust a meticulous Calculated approach without actually measuring the outcome impedance Out of the coupon? I would appreciate your pointer/Link to any written facts publishes at any given year along with your personal opinion. Best Regards Avigdor Jakubisnky Engineering Mgr. www.fibrolan.com --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------