Hi All This might be old news but I just came across this link to a Symmetricom presentation on timing measurements and thought it interesting.... _www.iee.org/OnComms/PN/communications/www.iee.org/OnComms/PN/com_ (http://www.iee.org/OnComms/PN/communications/005%20-%20Lee%20Cosart.pdf) regards Nigel GM8PZR