My personal experience is that even with field solver software, some additional adjustment was required based on actual results.  Once the parameter adjustments were identified, the accuracy of the field solver was pretty good.  However, I would not accept boards for a critical application without testing representative circuits or coupons from each panel.  There are too many process and material variables that affect impedance to rely strictly on calculations.

Don Vischulis

-----Original Message-----
>From: Avigdor JAkubinsky <[log in to unmask]>
>Sent: Dec 3, 2007 1:08 PM
>To: [log in to unmask]
>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
>
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