Hmm....Time to become imaginative and set it up so that such activity is billed BACK to Engineering. That way, it comes out of their budget whether they do it, or you do it?
Just like billing warrantee costs back to Manufacturing when they make it wrong, and bill to Engineering when they design it wrong. Robert On Tue, 3 Jul 2007 17:47:46 -0000 "Conway, Patrick R (Houston)" <[email protected]> wrote: > Robert- > > Perhaps you have the answer to the original question- > that an > EMC engineer can provide an accurate number for required > margin, but > only up to a certain point in the life of the product. > After that point > the question about margin no longer belongs in the EMC > department. We > can only provide a number that is relative to a point in > time. > > Doesn't it just stink that no matter how accurate I > perform my > R&D function, eventually someone else can impact the EMI > result more > then I can?!! > > > It also reminds me that I've known many R&D program > managers who > never cared about EMI margin. It was not their problem, > because after > launch to production, they moved on to the next project. > Thus leaving > the problem of continued compliance on the manufacturing > team (and the > EMC team!). > > The fact that a company is asking about margin, is a > sign of a > mature organization. > > > Best Regards, > > Patrick. > [email protected] > > > -----Original Message----- > From: Robert A. Macy [mailto:[email protected]] > Sent: Monday, July 02, 2007 10:39 PM > To: Conway, Patrick R (Houston) > Cc: [email protected] > Subject: Re: Internal Margins for Emissions Testing > > Ouch! if the origin of the potentially offending tone is > an upper > harmonic of a crystal source and all the units you just > tested used the > high quality Bulova IC which had a very well-behaved > 50-50 duty cycle > the power in the offending 6th harmonic is zero, thus the > reading is > also zero, or quite low. > > Then, since Engineering did not spec the duty cycle of > the Clock Chip, > Purchasing bought a whole bunch from ?? that cost half as > much, but had > a duty cycle of 35-65 and ZAP!! > suddenly there is a huge amount of energy at the 6th > harmonic which > unbeknownst to anybody now finds its way out. > > So how do you think in terms of statistical variance in > such a > situation? It's a little like predicting where the curb > is by measuring > the slope at the center of the road. > > Just very, very difficult to get there from here. > > Robert > > > On Tue, 3 Jul 2007 02:46:41 -0000 > "Conway, Patrick R (Houston)" <[email protected]> wrote: > > That is a great answer, the best so far regarding > statistical nature > > of our field (pardon the pun). > > Although not a fan of the measurement uncertainty cult > within > our > > discipline, I understand the intention and support the > result. > > > > > > It seems to me we are still missing 1/2 of the > "statistical" picture. > > Here is what I think - > > (I could be whacked out here- so please view this > with a > large > > portion of skepticism...) > > I think the measurement "system" includes two items: > > a) the measurement facility, and > > b) the EUT. > > > > I think the "measurement uncertainty" does a good job > of defining > > quantity a). > > But how do we define b), the variance of a product > from an > assembly > > line? > > > > > > The reason this is important to me is that I do not > own, operate or > > work in a test lab. > > So the only part of the above equation I can influence > is the b) > > > part. > > (that is of course, assuming that there truly is two > parts to > this > > "system", and I'm not whacked ) > > (- THAT may be too much to assume!) > > > > Has anyone on this list performed measurement to > understand the > > statistical RF nature of the EUT? > > I have not. > > And I'm not sure how I would start. > > > > > > > > Best Regards, > > > > Patrick. > > [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 ______________________________________________________________________
