EMC-PSTC Forum: An explanation from the IEEE; Request for help
Ladies and Gentlemen, As you know, last Friday the IEEE's listserver began reposting old messages to the forum, resulting in hundreds of messages filling member's inboxes. As soon as we were aware of the problem, the IEEE was contacted and the listserver was shut down for the day. An analysis subsequently revealed that messages were being rebroadcast to the server by one of the members. Needless to say, that member has been permanently unsubscribed from the forum. We apologize for the inconvenience and wasted resources that the above action caused. Please be aware that the forum is monitored by two admins as well as Rich Nute and myself. When you see an administrative problem with the forum, please help us by not broadcasting messages to the general forum. Simply direct your question or comment to either myself or Rich Nute. We have access to the resources and staff to correct problems as quickly as possible. Thank you for your tremendous patience and understanding. On a different subject, we are looking for an admin replacement. If you think you have 10 to 15 minutes a day that you could volunteer to enable the forum to continue operating, we'd love to hear from you. Even a temporary stint (few months) would be appreciated. Please direct your response to either myself or Rich Nute. Thank you very much. Roger Volgstadt volgstadt_ro...@tandem.com Rich Nute ri...@sdd.hp.com
Re: transportation environmental condition
In a message dated 98-03-09 15:13:04 EST, dmck...@paragon-networks.com writes: Ok, this is rather old but the atmosphere is still pretty much the same. Assuming your standing at sea level with 1 atmosphere pressure and +15C temp and you start to rise in altitude, you'll have roughly dependent upon alot of other factors ... AltitudeTemperature Pressure Approx Ratio of (feet) F Clb/ft^2 Altitude to sea level 0 + 59+ 15 2.12 x 10^3 0 20,000 - 12- 24 9.73 x 10^2 1/2 40,000 - 70- 57 3.93 x 10^2 1/5 60,000 - 70- 57 1.51 x 10^2 1/10 80,000 - 70- 57 5.81 x 10 1/50 100,000 - 41- 41 2.31 x 10 1/100 Assuming that you won't be shipping anything in an unpressurized cabin much above 60,000 ft, then testing for temp = -70C, pressure = (14.7 lb/sq.in.)/10 = 1.47 lb/sq.in. should do it. Speaking of humidity at temperatures near or below freezing doesn't really mean anything. -- From: regr...@esaote.com To: emc-p...@majordomo.ieee.org Subject: transportation environmental condition Date: Monday, March 09, 1998 8:43 AM Hello all! Does anybody know the foreseeable environmental condition (temperature, humidity, pressure) you have during transportation of a device on a plane? Of course they depend on flight heigth, but is it possible to get rough, common-sense data for the design of packaging? Many thanks Massimo --- ESAOTE S.p.A. Massimo Polignano Research Product Development Regulatory Affairs Via di Caciolle,15 tel:+39.55.4229402 I- 50127 Florencefax:+39.55.4223305 e-mail: regr...@esaote.com If you're speaking of CARGO compartment conditions, I believe that those are pressurized and heated to about 50 degrees F on passenger planes (otherwise, I suspect, passengers would get upset about their freeze-dried pets and luggage). Does anyone know of any standard conditions for cargo compartments? Mike Sherman FSI International msher...@fsi-intl.com [miksher...@aol.com]
Re: Seminars:EMC/EMI/ESDRelated to Corrosion and Material Reliability Issues
please someone make this person stop they have sent over 100 of these in the last few days
IEEE EMC SCV Meeting Notice, March 10. Sunnyvale, CA
The Santa Clara Valley IEEE EMC Society announces its March 10th Meeting. When/Where Tuesday, March 10, 1998. Building 157, Lockheed Martin, 3rd Avenue Sunnyvale, CA. 7:30 p.m. - 9:30 p.m. Topic/Speaker Fun With the Fourier Series Franz Gisin, Silicon Graphics Details Randomly pick up any EMC book or article that covers Fourier Series, and chances are the relationship between the time and frequency domains are explained in terms of either a symmetrical rectangular or trapezoidal waveform centered about the t = 0 axis. While they may serve as excellent introductory examples, they cannot be used to analyze more complex waveforms having unequal rise and fall times, overshoots, and undershoots. Nor can these simple waveforms be used to model more complex scenarios such as the spectral analysis of digital differential drives, where the concept of cancellation also requires phase information. This presentation develops a simple but effective method of obtaining the Fourier Series of complex waveforms, and then analyzes several common problems normally encountered in the EMC field. Topics that will be covered include: o Conceptual development of the Fourier Series from a piecewise linear periodic waveform. o An analysis of rectangular pulses that shows how decreasing the pulses width often results in increasing harmonic levels. o An analysis of symmetrical trapezoidal waveforms that show how a 10 MHz clock can actually have lower harmonic levels than a 1 MHz clock. o An analysis of non-symmetrical rise/fall time trapezoidal waveforms that shows how much reduction in harmonic levels one can obtain if only the rise (or fall) time were increased. o An analysis of trapezoidal waveforms having overshoots and ringing and how much overshoot and ringing can be tolerated. o An analysis of digital differential drivers and how the common perception that differential driven signals are somehow less prone to cause emission problems are not always true. BIOGRAPHY: Franz Gisin has a BS(EE) from the University of Idaho, and an MS(Applied Mathematics) from the University of Santa Clara. He has been active in the EMC community for over 20 years, and is currently EMC Manager at Silicon Graphics Inc. He is a senior member of the EMC Society, a member of the EMC Society Board of Directors, and the Steering Committee Chair of EMC '98. (Note: I am forwarding this to the group for Hans Mellberg who normally makes these announcements).
