I read in !emc-pstc that drcuthbert <drcuthb...@micron.com> wrote (in <cfefa50c9bcad21197470001fa7eba6b14121...@ntexchange05.micron.com>) about 'Fiber optic cable testing per EN 55022:1998 ?' on Fri, 10 Jan 2003: > >Chris, >some excellent points! My take on this is that a fiber optical cable has a >cutoff frequency that is way above the "RF" frequencies we are concerned >with. It just won't act as a waveguide for what we consider RF wavelengths. >However, I think the optical cable certainly does leak a bit at light >wavelengths.
That's a surprise; what evidence do you have? >It seems like one could perform light emissions and >susceptibility testing. Now most of our light wave communications use >cables. Sort of like if all RF communications was done in copper. With >nothing intentionally radiated, and with the cables operating as very poor >antennas, we might have no need for emission and susceptibility testing. On >the other hand, the FCC does not regulate radiated optical communications. >Maybe it's time to do so. With laser range finders, optical radar, IR remote >control, and other primitive devices we are accumulating pollution of this >part of the EM spectrum. Reminds me of spark transmitters spewing RF over a >wide frequency range. Street lights are the spark transmitters of the visible spectrum. > >Shouldn't an optical cable with a metal sheath be treated just like any >other cable? Hook it up during EMC testing? Yes, ALL cables, of whatever sort, are to be connected during testing. > >And as you point out, where is the transition from RF to light? RF >generation methods (such as gyrotrons, seem to peter out at wavelengths of >1000 microns while visible light begins at 0.7 microns. There seems to be a >huge no man's land in the EM spectrum. > Look up 'far infra-red'. This part of the spectrum is flooded with thermal radiation from objects at normal temperatures. But sources and detectors do exist. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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"
