RE: Pre-amps for EMC Use
You need to use a bandwidth of 1MHz above 1GHz remember. --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
RE: EN55022 Radiated Test Set up
I do believe you will find that the test labs will use the center of the turn table as the measurement point. --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
RE: ESD generators max Contact discharge level
Ed, the main difference has to do with the tip. An air discharge tip is rounded, not sharp. While a contact tip is sharp. Each one will allow a spark to jump the gap to the DUT, but in different ways. Michael Sundstrom Product Test Technician EMC Nokia Mobile Phones, Dallas PCC * Email michael.sundst...@nokia.com % Desk (972) 374-1462 *Mobile (817) 917-5021 * Fax (972) 374-0901 amateur call: KB5UKT --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
IEC 61000-4-3
Collogues, In this specification, is it stated anywhere if the unity field is a volume ( 1 cubic meter) or is it a plane location (the calibration plane)? I'm having questions raised about rotating the EUT (in 90 degree increments) (which now has us over testing the EUT because it is closer to the antenna by 0.3m at the 90 degree point) or under testing when tested at 270 degrees? I thought I had read somewhere that the unity field was the 1 cubic meter box at the (80cm) table top centered and aligned with the calibration plane? Michael Sundstrom Product Test Technician EMC Nokia Mobile Phones, Dallas PCC * Email michael.sundst...@nokia.com % Desk (972) 374-1462 *Mobile (817) 917-5021 * Fax (972) 374-0901 amateur call: KB5UKT --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
RE: Calibration of test equipment
I think there is a special requirement to keep the calibration equipment separate from the EMC equipment. In other words the calibration equipment can only be used for the calibration process and not for testing EMC. Michael Sundstrom Product Test Technician EMC Nokia Mobile Phones, Dallas PCC * Email michael.sundst...@nokia.com % Desk (972) 374-1462 *Mobile (817) 917-5021 * Fax (972) 374-0901 amateur call: KB5UKT --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
RE: Near Field Versus Far Field
I might add that the BEST way to do this is to only change one thing at a time, then retest. It's hard to tell what single change of the multiple changes attempted actually did the change. Michael Sundstrom Nokia Mobile Phones, PCC EMC Technician cube 4E : 390B phone: 972-374-1462 mobile: 817-917-5021 michael.sundst...@nokia.com amateur call: KB5UKT -Original Message- From: EXT Peter Poulos [mailto:pet...@foxboro.com.au] Sent: Friday, September 15, 2000 1:38 AM To: marti...@appliedbiosystems.com; emc-p...@majordomo.ieee.org Subject: Re: Near Field Versus Far Field Hi Joe. You asked for an explanation as to why the difference between the near and far field results. I think the replies so far have probably answered that question. I've tried here to give some help with the real problem of solving the excess emissions. From my own experience and discussions with colleagues, I've found you definitely need to do some (if not most) of the trouble-shooting while at the test site. Finding a problem then just returning to the lab to solve it usually leaves you with a lot of questions unanswered. That might not be much help this time but perhaps next time? The following is how I'd go about tackling the problem. I'm curious to see if there's anyone in the group who disagrees with my approach. As with any EMC problem, you've got to consider the source, the transmission medium and the victim. Obviously there's nothing you can change about the victim (the test antenna) but you should be able to narrow it down to work out the real source, and the means by which it is being radiated. For clues to the problem's cause to begin with I usually ask: (1) For the problem frequency, what's the most likely source? (2) For the problem frequency, what's the most likely source antenna? At 400MHz the wavelength is a bit under 1m (3x10^8 / 400x10^6 = 75cm) so any short cables (or at this frequency, maybe even long PCB track - like back-plane tracks?) that might make nice 1/2 wavelength or 1/4 wavelength dipole antennas would be the first I'd check out. Could also be a slot antenna effect in your enclosure - any seams or gaps in the box that are in this ball-park? Usually I'd try isolating the source by either disconnecting cables, turning off or unplugging cards, attenuating cable emissions with copious amounts of ferrite clamps etc and get the test engineer to do a spot check at the problem frequency as I tried eliminating each suspect. This is where the buckets of ferrite cable clamps, rolls of aluminium foil, shielding mesh and earthing straps come in to play. Here's where that near-field probe might come in handy too. This kind of troubleshooting though often requires a fairly intimate understanding of the way the equipment under test works so you can be confident about your assumptions and the conclusions you draw from the observed results. If the design engineer isn't actually at the test site, she/he should at least be accessible by phone to discuss the problems and make suggestions as to what to try. Using this technique, you can usually narrow it down fairly quickly to the source and antenna. If there's time, and its practical then I'd try some quick modifications to the problem circuit that's the source of the noise in order to get some reference of what changes cause what kind of reduction in the emission levels. Quite often though, you have to be aware that a change may solve the emission problem at the frequency you're working on, but result in the energy appearing elsewhere in the radiated spectrum causing the equipment to exceed the limit at some other frequency, especially if you've just modified the source antenna and not the signal causing the emission. Also note - although its difficult when you're rushing to get the problem fixed, it pays to make good records of what you change and what the results are - can help a lot later on. If you have the time at site to try a few different options (that are repeatable later), and get the highest 3 or 4 emission levels for each option at site, then if you can't find a solution you're happy with at the test site, it gives you a reference to work with back in the lab. For example, say that you found that: Design Change #1 resulted in 6dB reduction in the emission at 400MHz with other peaks (below the pass/fail limit) at 200MHz (3dB under), and 800MHz(8dB under) Design Change #2 resulted in 20dB reduction in the emission at 400MHz but caused the peak at 200MHz that went over the limit by 6dB with the peak at 800MHz reducing to 10dB under the limit. Design Change #3 resulted in 3dB reduction in the emission at 400MHz with other peaks (below the pass/fail limit) at 200MHz (9dB under), and 800MHz(7dB under) Then when you get back to the lab to try and find a good permanent fix, by repeating the changes you made at site, and comparing the emissions levels you observe for each in the lab with the results
RE: R: Conducted Emissions on Telecom Ports
Actually it's to reduce interference to one's own equipment, (if it emits it - it's also susceptible to it). It also has the effect of reducing interference to other near by equipment. Michael Sundstrom Nokia Mobile Phones, PCC EMC Technician cube 4E : 390B phone: 972-374-1462 mobile: 817-917-5021 michael.sundst...@nokia.com amateur call: KB5UKT -Original Message- From: EXT Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, September 07, 2000 11:43 AM To: Paolo Roncone; 'eric.lif...@ni.com' Cc: 'emc-p...@ieee.org' Subject: 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 -Messaggio originale- Da: eric.lif...@ni.com [SMTP:eric.lif...@ni.com] Inviato: mercoledì 6 settembre 2000 17.55 A: emc-p...@ieee.org Oggetto: Re: Conducted Emissions on Telecom Ports All, As a not-quite-outside-observer (strictly EN 55011 here) of this thread, it's not fun seeing LAN ports classified as telecom; IMO that's overkill for the folks using EN 55022. Up till now, I considered a port to be telecom only if it connects a client facility to a carrier's network (DSL, ISDN, T1 and so on). With repeaters every 5 meters, USB and 1394 can support a bus long enough to connect between adjacent buildings. So, I wonder if some fanatic will soon be promoting USB/1394 ports as telecom? If Chris is right, and the EN 55022 version of the old telecom port conducted emission standard was intended to protect other telecom signals in a bundle, then I would think that this test is clearly redundant to the immunity tests (61000-4-6 and -4-3) that offer the needed protection from the other end. Does this emission requirement appear to be a waste of time and money to anyone else? Regards, Eric Lifsey Compliance Manager National Instruments Please respond to Chris Allen chris_al...@eur.3com.com To: Pryor McGinnis c...@prodigy.net cc: david_ster...@ademco.com, emc-p...@ieee.org, gary.mcintu...@worldwidepackets.com, John Moore john_mo...@eur.3com.com (bcc: Eric Lifsey/AUS/NIC) Subject: Re: Conducted Emissions on Telecom Ports Pryor, Unfortunately, I don't think the definition is in question. It specifically states, that for the purposes of the standard, LANs are to be considered as telecomms ports as per section 3.6. It probably would have been less ambiguous if the standard defined Telecomms ports as Ports which are intended to be connected to the telecomms network OR LANs OR similar networks. As far as enforcement goes this will not change from the current method of enforcing compliance, primarily via the end user requesting DoCs and the relevent test data to back this document up. I believe the requirement goes back to a test that was performed under either VDE 0805 or 0806 (it was a long time ago that I had to perform the test). It was specifically aimed at unscreened cables over a certain length being placed in cable ducts and their impact on adjacent telecomms cables (if anybody remebers StarLan this was the product I was involved in). Chris. Pryor McGinnis c...@prodigy.net on 05/09/2000 20:54:51 Please respond to Pryor McGinnis c...@prodigy.net Sent by: Pryor McGinnis c...@prodigy.net To: david_ster...@ademco.com, emc-p...@ieee.org, gary.mcintu...@worldwidepackets.com cc:(Chris Allen/GB/3Com) Subject: Re: Conducted Emissions on Telecom Ports I do not disagree with the positions posted on this subject. My question is how does the EU interpret and enforce this requirement/definition. Pryor - Original Message - From: david_ster...@ademco.com To: emc-p
RE: Immunity Testing to EN55024
I think the reason you use the 12 of 16 points is so you will always have the minimum power necessary (leveled RF field) to insure a field strength of; at a minimum, the level calibrated for. (Due to the EUT distortion effect while running the test). Michael Sundstrom Nokia Mobile Phones, PCC EMC Technician cube 4E : 390B phone: 972-374-1462 mobile: 817-917-5021 michael.sundst...@nokia.com amateur call: KB5UKT -Original Message- From: EXT pwmc...@ra.rockwell.com [mailto:pwmc...@ra.rockwell.com] Sent: Wednesday, September 06, 2000 3:24 PM To: Antonio Cinquino Cc: emc-p...@ieee.org Subject: RE: Immunity Testing to EN55024 Antonio, The answer is that power is 180% greater (100% in the carrier, 40% in the USB, and 40% in the LSB). Voltage (RMS) is the square root of 180% (1.8) greater or 134% or 4.02 VRMS. This value may not have much practical sense except as a rough indicator of proper operation since the field value for the standard is determined without an EUT and most EUT's will distort the field when set in position. In addition to distortion the field is also set to +6, -0 dB (100% - 200%) on 12 of the 16 points and who's to say what the field should be within that range at the location of the monitor probe is for any particular frequency. I hope this helps, Paul McCoy --- 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 --- 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
Double posts?
Are we getting double posts for the server or is it a problem on my end? Michael Sundstrom Nokia Mobile Phones, PCC EMC Technician cube 4E : 390B phone: 972-374-1462 mobile: 817-917-5021 michael.sundst...@nokia.com amateur call: KB5UKT --- 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
