Hi Chas, Sorry to be late to the table, always happens when there's no food on it ;-)
Over the last 30 years in our lab it has varied. Starting out around when the CE mark first hit products tended to be noisy, but the circuits were running much slower the net result being a likelihood of failure under 200 MHz. Bad design and poor layout were the culprits. That improved as folks paid attention and about a decade ago we saw a significant number of designs that passed with margin first time. However, with the push to manufacture offshore we saw the emissions trend climb over the spec lines again. Some of this could be because switching got faster, but some was down to rudimentary mistakes being made over again. And some have been down to design changes by the contract manufacturer without telling the product owner. One other trend we have seen is manufacturers building stuff from supposedly CE marked sub-assemblies. The problem being in the end design, they are implemented way differently than the way they were tested during the sub assembly test. SMPS in particular are big offenders. All that said, we are running about 70% first time emissions pass rate if we exclude the problem designs referred to us to fix. I would be interested to hear a summary of all the replies you get should you have time. Take care, Derek > On May 24, 2021, at 9:46 AM, Grasso, Charles [Outlook] > <[email protected]> wrote: > > Hello EMC gurus! > > Calling all labs - In your experience how many products pass the > Unintentional Emissions > test first time? > > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > <[email protected] <mailto:[email protected]>> > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > <http://www.ieee-pses.org/emc-pstc.html> > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ > <http://product-compliance.oc.ieee.org/> can be used for graphics (in > well-used formats), large files, etc. > Website: http://www.ieee-pses.org/ <http://www.ieee-pses.org/> > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > <http://www.ieee-pses.org/listrules.html> > For help, send mail to the list administrators: > Scott Douglas <[email protected] <mailto:[email protected]>> > Mike Cantwell <[email protected] <mailto:[email protected]>> > For policy questions, send mail to: > Jim Bacher <[email protected] <mailto:[email protected]>> > David Heald <[email protected] <mailto:[email protected]>> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
