My response is that conducted path is so lossy as to be negligible. Consider that the 12 Vdc is developed by conversion from either aircraft 28 Vdc, or 400 cycles. In either case, that converter or power supply must meet the conducted emissions requirements of RTCA/DO-160, or its European equivalent. The 12 Vdc loads do not interface directly with aircraft power. Further, aircraft avionics, including radios, must meet stringent conducted susceptibility/immunity requirements on input power ports. Although I am not familiar with the European equivalent, I am sure it is the same way, because it was a British influence that placed similar requirements in RTCA/DO-160 and MIL-STD-461. I refer here mainly to Dr. Nigel Carter of the UK. These conducted susceptibility/immunity requirements simulate the effect of powerful radio transmissions coupling to the aircraft power bus, and are at levels orders of magnitude above the CE limits placed on aircraft avionics. I would say that it is a highly unlikely path for influencing aircraft avionics, although I would also say that if I, as an EMC engineer working for a major air-framer, were procuring a 12 Vdc supply for this use, I would push to characterize its input/output isolation from 0.15 - 400 MHz, for the sake of completeness. By input/output in this case I mean injecting a signal on the 12 Vdc output, and measuring the resultant signal on the aircraft power side. And I would measure this both differential and common mode, as I would expect different performance for different modes. But that would be strictly a CYA file, not a hard requirement.
---------- >From: Warren Birmingham <war...@comfortjets.com> >To: Ken Javor <ken.ja...@emccompliance.com>, emc-p...@majordomo.ieee.org >Subject: Re: New EU regulations - civil aviation >Date: Sun, Sep 15, 2002, 3:41 PM > > This is not so. Many aircraft now have personal 12v ports under each > seat for personal electronic devices. > > Warren Birmingham > Epsilon-Mu Consultants > (510) 793-4806 > email: war...@epsilon-mu.com > website: http://www.epsilon-mu.com > > > On Sunday, Sep 15, 2002, at 10:28 US/Pacific, Ken Javor wrote: > >> The point is that personal electronics carried on board an aircraft >> interact >> with the aircraft ONLY via the radiated emissions route. > ------------------------------------------- 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"
