I have also seen emission failures with IP devices using POE Injectors, if I remember correctly the emission margin dropped as you went up 10MHz, 100MHz to 1GHz. I would think that you would need to try a few different types to find a good one and of course unless you're working closely with the manufacturer there is no guarantee that what you test today will still pass tomorrow :-)
Rich On Mon, Oct 19, 2015 at 6:06 PM, Doug Smith <[email protected]> wrote: > Hi Chas and the group, > > > > It was the design layout of the PCB of the POE, and it was easy to see (no > PHY used). The magnetics may have played a part but the layout is terrible > in some of these devices. They are not designed by engineers of any > competence. In my article, I was very careful to make sure the end points > of the Ethernet connection and cable were not a factor, described in the > article. > > > > There is no PHY in this case, just inductors to inject the DC onto the > Ethernet connection. No active circuitry was involved as I remember. > > > > Doug > > > > Department for Continuing Education > > Oxford, Oxfordshire, United Kingdom > > -------------------------------------------------- > > Doug Smith > > P.O. Box 60941 > > Boulder City, NV 89006-0941 > > TEL/FAX: 702-570-6108/570-6013 > > Mobile: 408-858-4528 > > Email: [email protected] > > Web: http://www.dsmith.org > > -------------------------------------------------- > > > > > > On Mon, 19 Oct 2015 21:29:14 +0000, "Grasso, Charles" < > [email protected]> wrote: > > Hello Doug – in your tidbit you indicated that the pwb layout was (likely) > responsible for the > increased emissions at the below 100MHz range. It has been my experience > that when > the magnetics are placed inside a connector, that the emissions are more > influenced from > the imbalance in the cores and assembly that the layout. Nowadays there > is literally > no ambiguity in the layout – the traces go from the phy in the SoC to the > connector - > that’s it! [I am assuming that the design guidelines from the > connector/phy manufacturer > are being followed] Also how do you isolate the influence of the cable in > your measurements? > > > > After all the internal signal wires could be twisted differently as you > move the cable... Y/N?? > > > > > > Best Regards > > > > Charles Grasso > > > > Compliance Engineer > > > > Echostar Communications > > > > (w) 303-706-5467 > > > > (c) 303-204-2974 > > > > (t) [email protected] > > > > (e) [email protected] > > > > (e2) [email protected] > > > > > > *From:* Doug Smith [mailto:[email protected]] > *Sent:* Sunday, October 18, 2015 1:49 PM > *To:* [email protected] > *Subject:* Re: [PSES] PoE Injectors > > > > > > Hi Bill, > > > > > > > > Keep in mind that many POE adapters on the market will cause an emissions > problem because they are poorly designed and unbalance the Ethernet pairs > creating common mode currents. > > > > > > > > See my Technical Tidbit at http://www.emcesd.com/tt2011/tt080111.htm > > > > > > > > When you open some of them and look at the design, it is obvious they were > not designed by engineers. > > > > > > > > Doug > > > > > > > > Department for Continuing Education > > > > Oxford, Oxfordshire, United Kingdom > > > > -------------------------------------------------- > > > > Doug Smith > > > > P.O. Box 60941 > > > > Boulder City, NV 89006-0941 > > > > TEL/FAX: 702-570-6108/570-6013 > > > > Mobile: 408-858-4528 > > > > Email: [email protected] > > > > Web: http://www.dsmith.org > > > > -------------------------------------------------- > > > > > > > > > > > On Sun, 18 Oct 2015 18:50:30 +0000, Bill Owsley < > [email protected]> wrote: > > > > Somewhere in the references at the end, you might find which devices that > these standards apply to. > > > > There are number of exceptions. And there may have been changes since doc > was published. > > > > In the past I have emailed Victor with questions. > > > > - Bill > > > > > > > > > > > ------------------------------ > > *From:* Scott Douglas <[email protected]> > *To:* [email protected] > *Sent:* Sunday, October 18, 2015 2:04 AM > *Subject:* [PSES] PoE Injectors > > > > > Hello All, > > I am wondering if PoE injectors need to be ErP compliant? If so, what > efficiency level? Does anyone know of any such injectors that are > compliant? > > The injector would be used to power a product and not a switch, router, > or access point. > > Any and all comments appreciated. > > Regards, > Scott > > - > ---------------------------------------------------------------- > 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]> > > > > - > ---------------------------------------------------------------- > > > > 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) <http://www.ieee-pses.org/list.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]> > > > > - > ---------------------------------------------------------------- > > > > 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) <http://www.ieee-pses.org/list.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]> > > > - > ---------------------------------------------------------------- > > 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) <http://www.ieee-pses.org/list.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]> > > - > ---------------------------------------------------------------- > > 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) <http://www.ieee-pses.org/list.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]> > - ---------------------------------------------------------------- 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]>
