Derek, I like Ken Javor's method, very practical.
In regards to Luke Turnbull's method, I also used Excel, but slightly in a different process. I would scan in the graph in question as a jpeg or bitmap, and then use Paint (or something similar) so that I can get the x and y coordinates of the pixel. The pixels would be ones making the impedance values. I would take as many of these pixel x-y coordinates to replicate the graph. The x-y coordinates are then calculated to get the proper MHz and dB values. That's the short explanation. Doing it this way is probably not the easiest, but it had the following advantages- - The scanned in graph need not be perfectly laid squared onto the glass when scanning. It can be on an angle and the Excel program compensates for the "angle". - In comparing different graphs that are different in size and scale, this helped in making graph comparison easier. It is hard to visualize and get decent accuracy when graphs are in different sizes and scale factors. - Having the graphs in an Excel spreadsheet, made it easier to store the information for later use. I hope this helps. Richard 2007 PSES Chair 2007 PSES Web site: http://www.ewh.ieee.org/soc/pses/symposium/ 2007 PSES Symposium date: 22-23 October 2007 ===== Richard Georgerian Compliance Engineer email: [email protected] ===== - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
