Greetings all, In case there's anyone who missed it, the slides and text of the October talk can be found at: http://www.pjb.com.au/comp/lua/digitalfilter_talk/index.html Peter Billam http://www.pjb.com.au pjb at pjb.com.au (03) 6278 9410 "Follow the charge, not the particle." -- Richard Feynman from The Theory of Positrons, Physical Review, 1949