Re: [PSES] Conducted emissions for Split-phase 120/240V needs three-phase LISN?

It may be worth noting at any LISN using magnetic cores/elements in the 50uH bit, must be calibrated at the maximum rated current to verify that saturation isn't a problem. On 4/5/2024 9:56 PM, Brent DeWitt wrote: In my opinion, all of this is rather simple.  Any LISN, ANSI or CISPR

Re: [PSES] Conducted emissions for Split-phase 120/240V needs three-phase LISN?

In my opinion, all of this is rather simple.  Any LISN, ANSI or CISPR, references the noise to "ground".  Any conductor not being measured should be terminated in 50 ohms.  Whatever network used needs to make that so.  Take your pick. On 4/5/2024 9:43 PM, T.Sato wrote: On Fri, 5 Apr 2024

Re: [PSES] Radiated Emissions - How many points to QP?

This gets a bit more complicated for FCC regulations on emissions above 1 GHz, where the prescribed detector is an average detector (at 1 MHz RBW) and the peak limit is defined as 20 dB above that. On 4/5/2024 7:19 PM, Brent DeWitt wrote: That is what I expected you meant, but a bit confusing

Re: [PSES] Radiated Emissions - How many points to QP?

That is what I expected you meant, but a bit confusing based on the original topic.  You are certainly correct with respect to conducted emissions! On 4/5/2024 7:14 PM, rmm.priv...@gmail.com wrote: I was thinking conducted emissions in the context of average detectors. *From:*Brent DeWitt

Re: [PSES] I would like to hear your thoughts please

LL clocks and memory traffic, it is a tough thing to determine.  My opinion would be to preform the simplest pre-scan on each configuration and base the final, rigorous certification based on that knowledge. Brent Dewitt Milford, MA On 4/5/2024 6:47 PM, Lfresearch wrote: Hi folks, I would like

Re: [PSES] Radiated Emissions - How many points to QP?

Could you clarify when you would choose to use an average detector for radiated emissions between 30 and 1000 MHz? On 4/5/2024 6:39 PM, Ralph McDiarmid wrote: I’m having trouble with /“Of those disturbances above (L-20dB), where L is the limit level in logarithmic units, the disturbance

Re: [PSES] ESD testing - Contact Mode to plated metal surfaces?

I believe the language said something like: "the contact discharge tip shall be applied to any coating not expressly declared as insulative" Could be wrong though. Brent DeWitt Milford, MA On 9/18/2023 7:39 PM, Ken Wyatt wrote: Always had the impression the sharp end of

Re: [PSES] thoughts on ESD test lab problems

uld have test review processes in place to mitigate it. Had to pitch in. Brent DeWitt On 8/12/2023 1:47 PM, John Mcbain wrote: The basic question is, "How good is good enough?" Risk standards for product safety address that question to some extent, but it applies to every lab measur

Re: [PSES] Simulation of signal source under a pwb shield

d give you a decent approximation of the shield effectiveness. Take care my friend! Brent DeWitt, AB1LF Milford, MA On 7/21/2023 3:38 PM, Chas Grasso wrote: Hello experts and gurus!! I need to simulate the performance of a BLS (board level shield) and I am considering using the IEEE Std 2716-2022

Re: [PSES] Immunity test field strength, residential setting

se devices to outside data recording.  Nothing herre seems to apply! - Brent DeWitt My opinions have nothing to do with my current employer! On 7/21/2023 5:10 PM, John Woodgate wrote: Well, obviously 60601-1-2 doesn't apply, unless some clown claims that EV chargers are medical devices. The hig

Re: [PSES] FCC Part B questions

said they could not say it FAILED because 2dB was within their measurement uncertainty, so we could continue to ship and sell this product in Sweden. Has anyone else ever experienced this? Thanks, The Other Brian On Sat, Jul 8, 2023 at 8:28 AM Brent DeWitt wrote: Hi Brian.  It's

Re: [PSES] FCC Part B questions

thing is that labs would argue that, by being more rigorous an finding higher uncertainty, they would scare away customers who found less rigorous lab's smaller numbers attractive. Obvious puns about uncertainty resisted, Brent DeWitt, Lab Manager iRobot Milford, MA On 7/12/2023 11:02 AM, Patrick

Re: [PSES] FCC Part B questions

as it gets.  I'm measured rack mount systems with 30+ cables, and it's a nightmare.  I would suggest discussing your product in detail with the test house, or a consultant of your choice, to more accurately evaluate your margin needs. Brent DeWitt On 7/8/2023 10:17 AM, Jim Bacher, WB8VSU wrote

Re: [PSES] FCC Part B questions

uired" to pass any emissions limit.  Zero dB margin is still passing.  That said, measurement uncertainty in that range is generally 3-4 dB, so having a passing margin greater than that gives you some confidence that a re-test at another time and lab will still pass. Hope that helps. respectful

Re: [PSES] Resend of complete message on ESD thoughts

I'll jump in quickly to state my opinion: Contact discharge does not represent any "natural" mechanism I know of, but I prefer it because it seems to have the highest repeatability in revealing a device's vulnerability. -Brent, "If I can't be 'right', I at least want to be consistent about

Re: [PSES] Apple Files Patent for EMC Testing Chamber

My apologies for the typo.  I meant to type "I don't see anything that wouldn't be found to be "prior art"." On 2/23/2023 6:28 PM, Ghery Pettit wrote: Simple – Apple has the bucks and lawyers. Like you, I don’t see anything that isn’t prior art here, either. Ghery

Re: [PSES] Apple Files Patent for EMC Testing Chamber

I had the same thought Doug.  Maybe I need to read the patent more closely.  I don't see anything that would be found to be "prior art". -Brent On 2/23/2023 5:03 PM, Douglas Powell wrote: Am I missing something here? Apple Files Patent for EMC Testing Chamber

Re: [PSES] Adding more than one EUT

al change being made. Common case - let's sell this new combination of equipment as a single product. And of course, since "no changes are being made to the product" (wrong!) why bother telling the compliance engineer?  Been there! Best regards, John McBain On Sat, Feb 18, 2023 a

Re: [PSES] Adding more than one EUT

ive "power strip" for the additional units. In the first case, I would expect testing as a system, with all units attached In the second case, I would test a single unit. Another implication is for radiated emissions. What is the expected spacing between units in the typical users.

Re: [PSES] Dual antenna during RE test ?

Brings back memories!  MANY moons ago, I ran an OATS in the foothills of Colorado with lots of radio and TV ambients.  Thought I'd give the two antenna cancellation thing a quick experiment.  I had one antenna on out 10 meter test mast and put a second one on the edge of our 3 meter diameter

Re: [PSES] Chasing a specific frequency

amplitude won't change. Take care, Brent DeWitt On 5/6/2022 12:10 AM, Bill Owsley wrote: If you set the step function to the 63 MHz freq, and then step up, BW set a little wide to account for slight inaccuracy, do you find more emissions, energy, harmonics, at the steps ? If there is only th

Re: [PSES] Max Hold Quasi-peak ?

required. Respectfully, Brent DeWitt On 12/5/2021 1:45 PM, Amund Westin wrote: Some weeks ago I went to a test lab as an observer on a CE marking project (IT product). I participated on the radiated emission testing and some frequencies were above the limit line during the scan (peak m

Re: [PSES] Pure silicate paint as shielding for work areas

This seems like a good candidate for the classic SE measurement method of using a shield room pass-thru panel as the sample, with antennas on both sides.  At least it wouldn't require much material to try. Brent On 11/19/2021 10:50 AM, Patrick wrote: Ken- agree with you on all points.

Re: [PSES] Basic Schematic Creation Software

a purely graphic approach,"DIA" is a free alternative to Visio and allows structured drawings with some pre-defined electrical elements: Fare well, Brent DeWitt, AB1LF On 5/20/2021 1:42 PM, Manny Barron wrote: Hi Brian, I have found Spice to be useful for scenarios as you describe, i

[PSES] ESD verification

it shouldn't matter.  A half sheet of the stuff would certainly be cheap, light weight and I can get it today! Experiences and opinions welcome, Thanks, Brent DeWitt, AB1LF - This message is from the IEEE Product Safety

Re: [PSES] RF absorber for EMC room

absorbers!  They still work fine as absorbers, but tend to lose there self-extinguishing capability due to the migration of the retardant salts used in the manufacturing process for that purpose. Urethane fires are not something you want to experience. Respectfully, Brent DeWitt iRobot Bedford

Re: [PSES] SV: [PSES] Conducted emission - AC line filters makes it worse

You bet!  I've done it many times.  It's not perfect, but does give you a rough estimate.  The only requirement is being able to butcher the power cord so you can get tat the individual conductors.  Putting both through the clamp gives you the CM. Then take either L or N and twist it 180

Re: [PSES] FCC regulatory statements

I would interpret your radio as being compliant.  It accepts the interference just fine.  If you don't, that's another matter...Closest thing that the US has to an immunity standard.Respectfully,Brent DeWitt, AB1LF -Original Message- From: Richard Nute Sent: Oct 31, 2019 4:24 PM

Re: [PSES] Semi-Anechoic Chamber move

I used CIR Enterprises a few times.  2nd generation family business.  They are in Colorado, but do work anywhere in the country.  Nice folks. Brent DeWitt, AB1LF On 8/23/2019 11:04 AM, Ken Javor wrote: Re: [PSES] Semi-Anechoic Chamber move I cannot remember the company’ name

Re: [PSES] Automotive EMI testing

Not that I'm aware of, however the method needs to be documented in the test plan and (usually) agreed upon by the specific automobile manufacturer. Brent DeWitt, AB1LF On 8/17/2019 1:10 PM, Ken Javor wrote: Automotive EMI testing Question for folks familiar with automotive equipment EMI

Re: [PSES] Frequency range for conducted emissions

rounded up to 150 kHz. From a practical standpoint, if you stick with a 50 uH LISN, it starts to deviate from 50 ohms quite a bit as you go lower. Hope that helps. Respectfully, Brent DeWitt, AB1LF On 8/12/2019 4:36 PM, 06cee064502d-dmarc-requ...@ieee.org wrote: Hello group, Does anyone know

Re: [PSES] IEC 61000-4-9: Section 7.3 - use of a non-conductive table

Hi Richard, I'm assuming that by "magnetically conductive" you mean having a significant permeability. That's certainly a concern, but when you introduce a conductive but non-magnetic material in to the field, there is an opportunity for it to act as a shorted turn on the system, so keep

Re: [PSES] Question re: Measuring a signal in a noisy environment

Had a customer (or two) ask the same question.  My response was always: "more than it would take to fix your product".-Original Message- From: Manny Barron Sent: Apr 22, 2019 3:46 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Question re: Measuring a signal in a noisy environment

Re: [PSES] [EXTERNAL] Re: [PSES] EMI testing with ambient

Using the assumption below that both signals are BB and not synchronized, could you get away with something as simple as converting the noise amplitude and noise plus EUT amplitude to linear terms and subtract the noise? I believe there is precedence in CISPR regs for this approach. Brent

Re: [PSES] ISO17025 Antenna Calibration

nothing to gain by being a fan. Just am. Brent DeWitt Milford, MA From: Wiseman, Joshua [mailto:joshua.wise...@orthoclinicaldiagnostics.com] Sent: Tuesday, March 06, 2018 1:08 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] ISO17025 Antenna Calibration Oops, thanks for the correction

Re: [PSES] CE Marking HDMI Cables

Hi Scott, Which Directives do you think should apply? From: Scott Douglas [mailto:sdouglas...@gmail.com] Sent: Thursday, January 04, 2018 7:00 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] CE Marking HDMI Cables I am going around with an ODM making a HDMI cable for us. Standard

[PSES] EMC job opening in MA

* Senior EMC Technician * oUS, MA - Framingham * Apply * Job Description We are seeking a talented individual with experience and long-term interest in the EMC field. In this role, you will work with a diverse range of product design groups including,

Re: [PSES] God EMC practice

I agree with Jim that your calculated measurement uncertainty is the minimum margin that one should apply. This could be doubled by assuming the second assessing laboratory had the same uncertainty, but in the opposite direction! In practice, I believe that the products cabling, and therefore

Re: [PSES] Surge Suppression - Dos, and Don'ts

In my college summers, I worked as a radio technician for the Sierra National Forest in California. To make a _very_ long set of stories short, the behavior of high altitude lightning and antennas cannot be predicted, only analyzed after the fact. Brent DeWitt, AB1LF Milford, MA From

Re: [PSES] Quasipeak definition

it. Brent DeWitt, AB1LF Milford, MA From: Cortland Richmond [mailto:k...@earthlink.net] Sent: Monday, July 31, 2017 10:12 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasipeak definition https://www.amazon.com/Tekpower-TP188-Pocket-size-Analog-Multimeter/dp/B00064CH6A Eh? I got some

Re: [PSES] Quasipeak definition

Before even my time, but I was told that it was modeled after the classic "VU" meter used in sound recording, and for the same reason that Ghery mentions below. Brent DeWitt, AB1LF Milford, MA From: Ghery S. Pettit [mailto:n6...@comcast.net] Sent: Monday, July 31, 2017 2:16

Re: [PSES] application of CISPR 32 to EUTs with integrated radio transmitters

I can say, from personal experience, that high speed I2S bus communications with a modularly approve intentional radiator makes a significant change in the unintentional emissions. It may be/has been necessary to use a band notch filter at the fundamental intentional frequency to keep from

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

; > Date: Mon, 27 Feb 2017 21:13:53 -0500 > To: <EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> > > Subject: Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General > Use] > > On 2/27/2017 7:53 PM, Brent DeWitt wrote: >> I think Ken's ra

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

/2017 7:53 PM, Brent DeWitt wrote: > I think Ken's rational makes sense to me, since the 51.5 is derived from > 20*log(377). > > Sure, but now we're back to how close we are -- wavelengths -- to the emitter. 20*log(??) Low frequencies can be tricky, and I once had to double-check

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

I think Ken's rational makes sense to me, since the 51.5 is derived from 20*log(377). Brent DeWitt, AB1LF Milford, MA -Original Message- From: Macy [mailto:m...@basicisp.net] Sent: Monday, February 27, 2017 2:54 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] CORRECTION

Re: [PSES] Passive Loop Emissions [General Use]

S/m does actually make sense (to me) as the antenna factor units for getting magnetic field strength. Since the input to our SA or receiver measures voltage, we get back to current by multiplying the voltage times the conductivity, or 1 over the impedance. That doesn't directly get you to

Re: [PSES] lowest emissions 4k TV?

Thank you for the clarification Ghery. -Original Message- From: Ghery S. Pettit [mailto:n6...@comcast.net] Sent: Saturday, January 14, 2017 4:57 PM To: 'Brent DeWitt' <bdew...@ix.netcom.com>; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] lowest emissions 4k TV? The 4th par

Re: [PSES] lowest emissions 4k TV?

Gremmen [mailto:g.grem...@cetest.nl] Sent: Saturday, January 14, 2017 4:57 AM To: Brent DeWitt <bdew...@ix.netcom.com>; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] lowest emissions 4k TV? Exactly : Once the signal is unbalanced (whatever the reason) only shielding can attenuate the emi

Re: [PSES] lowest emissions 4k TV?

. Brent DeWitt, AB1LF Milford, MA -Original Message- From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com] Sent: Friday, January 13, 2017 12:19 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] lowest emissions 4k TV? " I suspect this is just equipment originat

Re: [PSES] lowest emissions 4k TV?

is more qualified to comment, but I believe there is work going on to reconcile the two. Brent DeWitt, AB1LF Milford, MA -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, January 12, 2017 7:20 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES

Re: [PSES] lowest emissions 4k TV?

] Sent: Wednesday, January 11, 2017 8:34 AM To: Brent DeWitt <bdew...@ix.netcom.com> Cc: EMC-PSTC@listserv.ieee.org Subject: Re: [PSES] lowest emissions 4k TV? I added the FCC search option initially based on my first search returning one example from a supplier whose North American

Re: [PSES] lowest emissions 4k TV?

d some success with a (now slightly old) Samsung 4k TV that wasn’t too noisy, model UE48JU7000T. James From: Brent DeWitt [mailto:bdew...@ix.netcom.com <mailto:bdew...@ix.netcom.com> ] Sent: 10 January 2017 01:57 To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>

Re: [PSES] lowest emissions 4k TV?

er Echostar Communications (w) 303-706-5467 (c) 303-204-2974 (t) 3032042...@vtext.com <mailto:3032042...@vtext.com> (e) charles.gra...@echostar.com <mailto:charles.gra...@echostar.com> (e2) chasgra...@gmail.com <mailto:chasgra...@gmail.com> From: Brent DeWitt [mailto:bdew..

Re: [PSES] lowest emissions 4k TV?

I should have mentioned that, in this case, we (Bose Corp.) are the test lab and it's our equipment we're testing.  We just came out with a couple of new audio-for-video devices that route HDMI through to pick out the 5.1 surround.  Had a heck of a time finding good sources and sinks.Not sure

[PSES] lowest emissions 4k TV?

for a WIKI site for the EMC community to post their findings on support devices. Nothing proprietary, just measurements of "off the shelf" support equipment like TVs, monitors and sources. Thanks all! Brent DeWitt Milford, MA --- This email has been checked for viruse

Re: [PSES] EN 300 328 - Bluetooth testing

The two things I've found to be problematic are band edge and spurious emissions.  So many of the other characteristics are cast in silicon that they've alreeady been worked out.Brent-Original Message- From: Jim Bacher Sent: Jan 9, 2017 9:04 AM To:

Re: [PSES] Practical ethics? -- text version

and integrity. May we all do our best. Brent DeWitt -Original Message- From: Cortland Richmond [mailto:k...@earthlink.net] Sent: Tuesday, December 27, 2016 1:52 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Practical ethics? -- text version On 12/27/2016 10:39 AM, John Allen

Re: [PSES] Public view of this email server?

Many companies use the legal term of “at will” employment. It pretty much gives an employer the right to dismiss without disclosing any motivation. From: Ted Eckert [mailto:07cf6ebeab9d-dmarc-requ...@ieee.org] Sent: Tuesday, November 22, 2016 11:49 PM To: EMC-PSTC@LISTSERV.IEEE.ORG

Re: [PSES] Measurement Uncertainty Above 18 GHz

, we may have common ground for agreement with respect to the results. Standard disclaimers for personal opinion apply! Brent Dewitt, AB1LF Milford, MA From: dward [mailto:dw...@pctestlab.com] Sent: Sunday, October 30, 2016 1:46 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES

[PSES] HDMI questions

, or to the 9777? As is probably obvious, I don’t have a whole lot of experience with HDMI video. Thanks all! Brent DeWitt, AB1LF Milford, MA --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

Re: [PSES] Antenna gain measurement standard

I forgot to say that, depending on the frequency (higher is worse) it’s almost impossible to know what the maximum antenna gain you will find in a full spherical is versus three orthogonal cuts. In my products I’ve seen 7dB difference at 5 GHz of an antenna in a product. It’s also worth

Re: [PSES] Antenna gain measurement standard

Hi Stephen, Lots of questions are required to answer your question with any accuracy. I assembled a system to do spherical patterning to our product antennas above 1 GHz, so I have some exposure to the problems. A few of those questions: - Are these product antennas rather than

Re: [PSES] AMA Warns of Harm from LED Streetlights’ Blue Light

Just came back from Morocco in May and didn’t see any amber headlamps. Maybe times have changed. Brent G DeWitt Senior EMC Design Engineer Bose Corporation The Mountain Rd, MS 450 Framingham, MA 01701 508-766-1494 From: Doug Powell [mailto:doug...@gmail.com] Sent: Wednesday, June 22,

Re: [PSES] Pre-Amp mounted to antenna

Not exactly "turn key", but Mini-Circuits will sell you connectorized bias Ts and DC blocks that will get the job done. Hope that helps, Brent DeWitt Milford, MA From: Kunde, Brian [mailto:brian_ku...@lecotc.com] Sent: Tuesday, March 15, 2016 1:27 PM To: EMC-PSTC@LISTSER

Re: [PSES] Source for Quality Video Cables

ly doesn't address EMC concerns and the performance of the cables in radiated emission shows it. YMMV Brent DeWitt Milford, MA -Original Message- From: Kunde, Brian [mailto:brian_ku...@lecotc.com] Sent: Wednesday, March 02, 2016 4:56 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PS

Re: [PSES] Spectrum analyzer and noise floor

Generally pretty correct Ralph. The only "picky" point I would have is about #2. The pre-amp really doesn't lower the noise floor created by #1. It raises the signal level further above it. Best of luck, Brent DeWitt Bose Corporation Framingham, MA From: McDiar

[PSES] 4k TV/monitor?

Does anyone have a recommendation for a 4k capable tv or monitor to use for emissions testing?  I have a couple of samples of Samsung U28E590D which pass radiated emissions above a GHz, but not by much (3dB).Any positive experiences would be welcomed!Brent DeWitt

Re: [PSES] Stricter limits than legal (CISPR11, IEC, etc,) Where?

Nobody seems to be asking _why_ margin is important or not. I expect no one believes airliners are going to fall out of the sky or grandma’s pacemaker to stop if a product is 10 dB over the FCC/CISPR Class B limits for radiated emissions. So why? For emissions (not immunity, that’s a

Re: [PSES] Best design practices to keep CM currents off a USB 2/3 cable given an unshielded enclosure?

ier what to complete their journey. No general leads here, but generally layout dependent. I'm sure I'm preaching to the choir on most of this, but you did ask. ;-} Best regards, Brent DeWitt From: Ken Wyatt [mailto:k...@emc-seminars.com] Sent: Thursday, September 10, 2015

[PSES] HDMI extension cable recommendation?

I’m looking for a good quality HDMI extension cable for test use. Price is not an issue since I only need a few. Does anyone have any recommendations based on their shielding and build quality? Thanks! Brent DeWitt Senior EMC Engineer Bose Corporation

Re: [PSES] Calculating Reflection Angles on OATS/SAC

Hi James, The image concept again is useful. By definition, the ground reference plane is at zero potential. For that to be true, charges on the real antenna and its image must be equal and opposite. Put a plus on one end of a dipole and a minus on the other and look at them. If they are

Re: [PSES] Calculating Reflection Angles on OATS/SAC

field propagation, which may not be the case depending on the range and frequency. Hope that helps, Brent DeWitt, AB1LF Milford, MA -Original Message- From: CR [mailto:k...@earthlink.net] Sent: Saturday, August 01, 2015 8:01 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Calculating

Re: [PSES] air activated finger probes

Look at the Lego Technic line. In the past they had a number of kits with plastic pnuematics. I've used them in the past to build remote button pushers.-Brent-Original Message- From: Ted Eckert Sent: Nov 4, 2014 11:24 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject:

Re: [PSES] Human fingertip capacitance.

a few hundred pF from the body of the stylus to ground to simulate a big human body full of salt water, but mechanical design is vastly simplified. This one works well and has replaceable tips for when things wear out: http://musemee.com/us/index.php Respectfully, Brent DeWitt Milford, MA

Re: [PSES] Audio sources, class D digital amps, radiated emissions, and philosophy

is that I highly recommend that any EMC engineer first familiarize themselves with the characteristics of the amplifier chip vendor before launching into troubleshooting. It will save you time in the long run! With respect, Brent DeWitt, Senior EMC Engineer Bose Corporation, Framingham MA From

Re: [PSES] Mode-stirred, Mode-tuned, Reverb - what's the difference?

Title: Re: [PSES] Mode-stirred, Mode-tuned, Reverb - what's the difference? The small chamber with the lights was the work of Mike Hatfield, then of NSWC Dahlgren.Brent DeWitt-Original Message- From: Luke Turnbull Sent: May 10, 2013 7:07 AM To:

Re: [PSES] LED Chamber Lighting

One of my colleges here tested the X-prize Phillips bulb for radiated emissions in a simple desk lamp in our chamber. A single bulb _barely_ passed Class B at three meters. YMMV! Brent DeWitt Bose Corporation Framingham, MA -Original Message- From: Kunde, Brian brian_ku

Re: [PSES] 61000-4-3: Rate of application of field

In a previous life working with medical equipment (2 Hz modulation, 15 second dwell), I found that the transient from turning on the modulation at a random phase angle was sometimes problematic. My solution was to use an arbitrary waveform generator as the external modulation source to the signal

RE: Question on RF conversion

short of a longer dissertation and ask you to more fully describe the problem. With respect, Brent DeWitt -Original Message- From: owner-emc-p...@listserv.ieee.org [mailto:owner-emc-p...@listserv.ieee.org]On Behalf Of lisa_cef...@mksinst.com Sent: Thursday, January 13, 2005 6:31 AM

ISO 14971 question

Scanning the broad range of knowledge on theis list I have the following question: Does anyone know of a standard other than 60601-1-2 that untilizes ISO 14971 risk analysis under normal rather than single fault conditions? Thanks! Brent DeWitt Datex-Ohmeda Louisville, CO This message

RE: Q. on Res Bandwith performace traceabiity

is dB referenced to one volt. The factor of two difference in power and voltage is simply the effect of pulling the log of the voltage squared term outside of the log operation. Not a great mystery. Are we done now? Brent DeWitt From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p

RE: Synchronizing DC-DC converters to reduce emissions?

within the CISPR bandwidth. Brent DeWitt From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Pat Lawler Sent: Wednesday, July 30, 2003 8:31 AM To: EMC-PSTC Subject: Synchronizing DC-DC converters to reduce emissions? We are designing a switching power

RE: RTTE for Medical Devices?

. These requirements are somewhat more stringent than the RTTE directive. That probably doesn't help much, but it's a bit more information. Regards, Brent DeWitt From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of D.Han Sent: Friday, July 18, 2003 4:20 PM

RE: EMC-Related Functional Safety

much less than a microwave oven to cause medically critical control electronics to misbehave. Regards, Brent DeWitt Datex-Ohmeda Louisville, CO From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Gregg Kervill Sent: Tuesday, February 11, 2003 12:14 PM

OFF TOPIC, was RE: David Sproul...UL creepage limits ;~)

to be at a Checker Auto last year when one of their personnel blew up a customers battery (in the car) while using their system tester. Quite the bang. Fortunately, no one was hurt. Regards, Brent DeWitt Peter L. Tarver peter.tar...@sanmina-sci.com@majordomo.ieee.org on 10/10/2002 08:58:40 AM Please

Re: Difference between Receivers and Spectrum Analyzers

that an S.A. is only a qualitative device. Regards, Brent DeWitt --- 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

RE: Surge and EFT test equipment for AC, DC, and signal ports

inputs and 12kW outputs. There may be a premium there. Respectfully, Brent DeWitt -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Warren Birmingham Sent: Monday, September 23, 2002 8:03 PM To: Jim Eichner Cc: emc-p

RE: Radiated immunity test

that passed field uniformity, but had clipped power amplifier output under modulation. Respectfully, Brent DeWitt -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of KC CHAN [PDD] Sent: Monday, September 23, 2002 7:57 PM To: emc-p

Transmission line formula?

Anyone have a formula for calculating the Z0 of two parallel rectangular pieces of metal tubing in air? I'm designing a log-periodic antenna and need to get the boom transmission line spacing right. Thanks! Brent DeWitt Datex-Ohmeda --- This message

RE: made in xxxx requirements?

for country of origin marking, either in the US or EU. Can anyone point me in the direction of an answer? Thanks all, Brent DeWitt Datex-Ohmeda Louisville, CO --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list

made in xxxx requirements?

This is not my usual area of interest, but a question came up about regulations for country of origin marking, either in the US or EU. Can anyone point me in the direction of an answer? Thanks all, Brent DeWitt Datex-Ohmeda Louisville, CO

Re: Re[2]: Non-metallic tables.

that indicates more that 8dB variation across the corners of the table at 1GHz. Regards, Brent DeWitt Datex-Ohmeda Louisville, CO brian_ku...@leco.com@majordomo.ieee.org on 07/02/2002 08:19:23 AM Please respond to brian_ku...@leco.com Sent by: owner-emc-p...@majordomo.ieee.org To: emc-p

case of units

a name. Also rather interesting that we have no trouble using G for both Giga and Gauss. Just Sunday evening thoughts. Brent DeWitt -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of bogdan matoga Sent: Saturday, June 22

Re: Input voltage range - EN61000-4, 5 and 6

In the very specific case of Medical devices, the newest edition of IEC 60601-1-2 specifies -5 testing at the extreme ends the range of continuously adaptive supply and in each range of a switched range supply. Regards, Brent DeWitt gunter_j_ma...@embraco.com.br@majordomo.ieee.org on 04

RE: Committee Memberships

Martin, To the best of my understanding, for international committees (IEC and TAGs), it requires the endorsement of your nomination by the appropriate National Committee. ANSI typically reviews resumes directly for committee applicants. regards, Brent DeWitt -Original Message- From

RE: High Frequency Pre-amp

Robert brings up a very good point. It is the main difference between a $4 ERA monolithic amp from MiniCircuits and a packaged $1200 Miteq amp. While saying that, I think MiniCircuits is a great company with a range of products that are well characterized and worth every penny. Regards, Brent

RE: 2 Phases in North America

. The math seems to work. WRT Cortland's post, I guess I don't see ground (or close to it neutral) as having a phase. If that is believable, then a single phase system is not so hard to believe. Just a few thoughts, Brent DeWitt -Original Message- From: owner-emc-p...@majordomo.ieee.org

IC marking ?

! Brent DeWitt --- 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

RE: EMC test table construction plans

(below the critical angle) dielectric reflection. The signal was strongest when aligned with the corners of the rectangular table. Brent DeWitt Datex-Ohmeda Louisville, CO -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf

board scanning on the cheap (sort of)

it's all done, I should be able to play a frequency swept movie of the board on an intensity graph. The cheaper way to do this would be to find an older X-Y plotter and skip the height variation. If I ever get the beast done, it will be open source to LabVIEW users. Best regards, Brent DeWitt

  1   2   >