>-----Original Message----- >From: Hans Mellberg [mailto:[email protected]] >Sent: Thursday, January 09, 2003 4:59 PM >To: John Woodgate; [email protected] >Subject: Re: Fiber optic cable testing per EN 55022:1998 ? > > > >As a matter of fact the local SCV EMC society paper next week >is about EM radiation >from fiber optics. No, not from the glass or plastic itself!, >but from the metalized >reflector coating and also from the proximity of the Tx diode >next to the connector. >Actually measurable radiation! > >--- John Woodgate <[email protected]> wrote: >> >> I read in !emc-pstc that Tom Cokenias <[email protected]> wrote (in >> <v04205511ba4377eaa41d@[10.10.10.79]>) about 'Fiber optic >cable testing >> per EN 55022:1998 ?' on Thu, 9 Jan 2003: >> >> >I'm wondering how to handle fiber optic cables under the >new EN55022 >> >going into effect August 2003. Measurements are supposed >to be made >> >on telecommunications cables, and fiber optic cables are being used >> >for telecommunications. From my reading of the standard I >don't see >> >that they would be excluded, but neither do I see how they >should be >> >tested. >> >> Can you see any mechanism by which they would emit EM radiation below >> 400 GHz, or conduct it, or lack immunity to it? >> >> You don't have to do tests that are clearly not sensible. >> -- >> Regards, John Woodgate, OOO - Own Opinions Only.
Here's a link to a steel armored fiberoptic cable. I suppose the steel is a ribbon wrapped in a helix around the cable, somewhat like the old "BX" electrical cable. Currents induced in the steel would have to flow along the helix, which would electrically present as an inductor. Random conductive paths would link one turn of the helix to the next, shorting out the voltage >from turn to turn. With sufficient induced current, a bit of corrosion, and maybe a little motion, this has the potential to create some interesting noise. http://www.mohawk-cdt.com/main.html Regards, Ed Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
