It is not a "symbol rate". It is PLL in the Ethernet PHY that gets turned on as soon as you get a 100 or Gig link. So, when you connect the remote end, the 100 or Gig link comes up and you see it. The emission level, however, depends on many factors, mainly the PHY itself, the transformer, the PCB andsystem/enclosure design. Regards, Neven
-------------- Original message -------------- From: "Stu Benner" <[email protected]> Derek, 125 MHz is the symbol rate of 100 Mb and 1 Gb Ethernet. Ensure that the shield of the cable, if used, is terminated properly at the chamber penetration, the UUT, and at the exercising equipment. If there is an increase in emissions when the shielded cable is installed, this could indeed indicate significant common mode signals are being coupled onto the outside of the shield of the cable. Regards, Stu Benner www.emcwizard.com <http://www.emcwizard.com/> From: [email protected] [mailto:[email protected]] On Behalf Of Derek Walton Sent: Wednesday, October 04, 2006 2:38 AM To: IEEE EMC Discussion Group Subject: Ethernet emissions HI All, I have a system on test that has a single very strong emission at about 125 MHz. Is this an Ethernet related frequency? It appears to jump 20 dB when the receive end, outside the chamber, is plugged in. Also, with unshielded cables it's not there. With shielded its about 30 dB up at the same frequency. Anyone have suggestions as to the source? Thanks, Derek Walton L F Research - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discus! sion li st. 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 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 ______________________________________________________________________ - ---------------------------------------------------------------- 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
