Paolo, Physics does work the same on both side of the Atlantic, but human rationale does not necessarily!
Tania Grant, tgr...@lucent.com Lucent Technologies, Switching Solutions Group Intelligent Network and Messaging Solutions > ---------- > From: Paolo Roncone[SMTP:paolo.ronc...@compuprint.it] > Reply To: Paolo Roncone > Sent: Friday, September 08, 2000 3:51 AM > To: 'Ken Javor'; 'Cortland Richmond' > Cc: 'emc-p...@ieee.org' > Subject: R: R: Conducted Emissions on Telecom Ports > > > Ken and Cortland and many others that entered this subject : > > First, radiated emissions are best measured with radiated (not conducted) > measurements. There is a correlation between CM currents and RE but that's > not all (resonances, cable layout etc. count a lot). > Second, you say that CE are easier to measure than RE ? Agree if you talk > about emissions on AC power cords (as per CISPR22 and FCC part 15). But > for the new requirements on telecom ports, I suggest you to take a look at > the new (3.ed.) CISPR22 or EN55022 (sec. 9.5 + annex C.1) and may be you > change your opinion ! > Radiated emissions above 30 MHz are already covered. > If you wanna take care of lower frequencies (< 30 MHz) take a loop antenna > (remember the old VDE rules ?) and measure radiated H-fields with your > system in the same (typical) layout used for the higher frequencies (with > whatever cables you specify, UTS, STP etc.). I am sure that is much > quicker, easier and repeatable than all the nonsense (ISNs, CDNs, clamps, > current probes, capacitive probes, ferrites, 150 ohm resistors, signal > generators, impedance measurements, voltage measurements, current > measurements and more) in the new CISPR22. > As for the question of "outside world", I think in this ever more > connected world the border line between INSIDE and OUTSIDE is getting more > and more blurred, BUT I also think that a line must be drawn by the > standard bodies, otherwise it's gonna really get too much confusing (hope > some CISPR/CENELEC member gets it). > If we spill over the line (office, floor, building... whatever), emissions > requirements are triggered. But within that line it's to be considered an > "intra-system" (what's the system ? that's another good question to be > settled) interference potential and the manufacturer should take care of > it without need of enforcement because he has all the interest in making a > product (system) that works properly and reliably. > > One last point: based on David Sterner's note, looks to me that North > America has a pretty extensive Ethernet and-the-like network. I honestly > don't know if the FCC has already enforced emission limits on LAN ports. > Anyway, based on David's note looks like there are no complaits of > interference with TV and telephones. And please note, this is the very > bottom line of it. Emission limits should be intended to protect public > services ... and physics works the same on both sides of the Atlantic... > or not ???? > > My personal opinion ... > > Paolo > > > > > > > -----Messaggio originale----- > Da: Ken Javor [SMTP:ken.ja...@emccompliance.com] > Inviato: giovedì 7 settembre 2000 18.43 > A: Paolo Roncone; 'eric.lif...@ni.com' > Cc: 'emc-p...@ieee.org' > Oggetto: Re: R: Conducted Emissions on Telecom Ports > > Although I don't work commercial EMC on a regular basis and I do not know > over what frequency range the telecom port CE are controlled (I assume > here > 150 kHz - 30 MHz), I believe that there is a mistaken premise inherent in > the comments to which I am responding. The purpose of controlling common > mode CE on any port is not to protect equipment at the other end of the > cable, or other co-sited cables, but rather to control radiated emissions > in > a frequency range in which CE are easier to measure than RE. In turn, the > purpose of controlling RE is to protect broadcast radio reception. > ---------- > >From: Paolo Roncone <paolo.ronc...@compuprint.it> > >To: "'eric.lif...@ni.com'" <eric.lif...@ni.com> > >Cc: "'emc-p...@ieee.org'" <emc-p...@ieee.org> > >Subject: R: Conducted Emissions on Telecom Ports > >Date: Thu, Sep 7, 2000, 9:45 AM > > > > > > > Hi Eric, > > > > I 100% agree with you. The scope of emissions standard should be to > protect > > the "outside" (i.e. public) environment from interference. So only ports > > that connect to public telecom networks should be covered by the > standard. > > The problem is (as pointed out in one of the previous notes) that the > new > > CISPR22 / EN55022 standard clearly includes LAN ports in the definition > of > > telecommunications ports (section 3.6) no matter if they connect to the > > "outside world" or not. > > > > Regards, > > > > Paolo Roncone > > Compuprint s.p.a. > > Italy > > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > 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: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > >
<<application/ms-tnef>>
