Re: Measuring a ferrite performance

As usual, Ed's advice is practical and economical to implement. I would add the following to make it more comprehensive. Ed's test measures insertion loss. You can calculate impedance from that. At frequencies where the impedance is high Ed's test works well. At frequencies where the impedance

Re: CISPR 25 Conducted Emissions (Current Method)

A major error was made in that attachment. The transfer impedance of a current probe is not a loss. It is a conversion factor. Current passing through the window yields a potential at the probe output, when loaded by its proper termination impedance, typically 50 Ohms, or 34 dB Ohms. That is i

Re: CISPR 25 Conducted Emissions (Current Method)

It is true that the unit dB Ohm has to be interpreted in context. However that does not change its utility. Current probe transfer impedance and shielding transfer impedance both have units of dB Ohm. What would be a better substitute? > From: John Woodgate > Reply-To: John Woodgate > Date:

Re: Measuring a ferrite performance

Charles Grasso asked, >> I have a requirement to test the performance of ferrite bead (one that that can fit over a power cord) to 500MHz for qualification of alternate vendors. I have an impedance analyser - but it only goes to 40MHz. Does anyone have a good way to verify ferrite impedance.??

RE: Measuring a ferrite performance

Without knowing whether you are measuring a cable ferrite or on-board SMT parts, here's my 2-cents comment: In order to achieve good results of the ferrite performance up to 500 MHz, we need to be careful: 1) build the test fixture such that the characteristic dimension of the overall test fix

Re: CISPR 25 Conducted Emissions (Current Method)

I read in !emc-pstc that scott@jci.com wrote (in ) about 'CISPR 25 Conducted Emissions (Current Method)' on Thu, 18 Dec 2003: >Please read the attached document that he assembled for the details. Not relevant to the question, but I'm very disappointed to see 'dB(ohm)'. The point is that this

RE: NEBS Compliance

Greetings All, I believe the NEBS Criteria Levels is from SR-3580, not SR-5270. Regards, Richard = Richard Georgerian Compliance Engineer Carrier Access Corporation 5395 Pearl Parkway Boulder, CO 80301 USA Tele: 303-218-5748 Fax: 303-218-5503 mailto:rgeorger...

RE: NEBS Compliance

This is indeed the textbook description of NEBS levels, and probably was extracted out of SR-5270 (I think - somebody else might want to correct that). That is only part of the story however. Each of the RBOC's defines what tests they require before it meets their own definition of level 1, 2 or

Re: Measuring a ferrite performance

Don't buy a 500 MHz analyzer. You'll end up having an analyzer that still won't be what you may need. Rent it for the ferrite test, and later buy a decent network analyzer :) It is possible to find decent used equipment that isn't terribly expensive (in relative terms) these days. Neven > > At t

Re: Measuring a ferrite performance

Don't buy a 500 MHz analyzer. You'll end up having an analyzer that still won't be what you may need. Rent it for the ferrite test, and later buy a decent network analyzer :) It is possible to find decent used equipment that isn't terribly expensive (in relative terms) these days. Neven > > At t

Thanks for the responses

Thanks for the responses. The component engineering group are asking for impedance vs freq so that they can compare the graphs to the specs. I was thinking of using a network analyser... Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fa

Re: Measuring a ferrite performance

HI Chas, I have a Network analyser that will go to 500 MHz... Derek. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: majord...@ieee.org wit

RE: Measuring a ferrite performance

Ed, Steward ferrite discusses this question their website. Other than noting it was there I didn't read it so I can't speak to the quality of the article, but one would assume these guys should know how to make such a measurement. Gary From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Thursd

RE: Measuring a ferrite performance

Charles, You can do the same thing that ED PRICE suggested if your spectrum analyzer has a tracking generator option installed. Just replace the signal generator by the tracking generator. We have characterized ferrite clamps and such in the same manner. Best Regards, Scott Mee Johnson C

RE: Measuring a ferrite performance

Low cost method: An MFJ (mfj enterprises) MFJ-269B impedance analyzer covers 1.7-170 MHz and 420-450 MHz. It will give you the R and X up to 600 ohms. Price is about $370. A very useful item to have around the lab. Dave Cuthbert Micron Technology From: owner-emc-p...@majordomo.ieee.org [m

RE: Measuring a ferrite performance

-Original Message- From: Grasso, Charles [ mailto:charles.gra...@echostar.com] Sent: Thursday, December 18, 2003 9:40 AM To: 'emc-p...@majordomo.ieee.org' Subject: Measuring a ferrite performance Greetings all: I have a requirement to test the performance of ferrite bead (one tha

Square root formula (was no subject)

That is the formula for the geometric sum of 2 RMS quantities. For example, if you have a primary circuit that has a working voltage of 230Vrms and a secondary circuit with a working voltage of 32Vdc, the RMS working voltage BETWEEN the two circuits is determined with the formula, giving you 232

Re: Measuring a ferrite performance

At the risk of collecting the ire of the instrument manufacturers, look at buying an "up to 500MHz" network analyzer. Do an in house demonstration. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International E

Re: sqroot(a^2 + b^2)

Brian, That is the rms value of two "uncorrelated" ac voltage sources. For noise, this is the way uncorrelated noise power adds. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronic

RE: CTL Decisions - the situation for Europe

Art Thanks for that. Four points: 1) Slight error in your URL, should be http://www.cbscheme.org/ctl/decisions.htm 2)This an IEC CB site, not an EU/CENELEC site, so the "official" validity of anything stated thereup-on is questionable. 3) Yes, these also give the OSM decision sheets, but th

Measuring a ferrite performance

Greetings all: I have a requirement to test the performance of ferrite bead (one that that can fit over a power cord) to 500MHz for qualification of alternate vendors. I have an impedance analyser - but it only goes to 40MHz. Does anyone have a good way to verify ferrite impedance.?? Thanks

Re: NEBS Compliance

Trevor, Please check out www.nebs-faq.com for answers to common NEBS questions. Best regards, Dave www.lorusso.com Trevor Chainey tchai...@telesoft-technologies.com wrote: > >This is a multi-part message in MIME format. > >Content-Type: text/plain; > charset="iso-8859-1" >Content-Tran

Re: square root

I don't know about voltage, but in maths it is the hypotenuse of a right-angled triangle! Regards, Neil Helsby Original Message dated 18/12/2003, 15:50:17 Author: "Brian O'Connell" Re: : Good People What is the basis of this formula for working voltage ? sqroot(a^2 + b^2) thanks, Brian

Re:

Sorry, the second line was missed from my earlier reply. I don't know about voltage, but in maths it is the hypotenuse of a right-angled triangle! I therefore presume it is the measured voltage calculated from knowing the active and reactive components of the voltage. Regards, Neil Helsby Origi

Re:

I read in !emc-pstc that Brian O'Connell wrote (in ) about '' on Thu, 18 Dec 2003: > >Good People > >What is the basis of this formula for working voltage ? > > sqroot(a^2 + b^2) > It the HIPOTenuse? (;-) Or perhaps the r.m.s. value of a direct voltage a and an r.m.s. alternating

Re: CTL Decisions - the situation for Europe

I read in !emc-pstc that Ing. Gert Gremmen wrote (in ) about 'CTL Decisions - the situation for Europe' on Thu, 18 Dec 2003: > CTL decisions are not relevant within the EC compliance system. >  >Whether a manufacturer chooses to declare compliance based or not >based on a >CT

Re: CTL Decisions - the situation for Europe

Hello All, I believe it was mentioned previously, but the link for the CTL Decisions may have gone unoticed by some; Both the CTL Decision Sheets and the OSM Decision Sheets are available online at: At this same location, there is also a description of

CISPR 25 Conducted Emissions (Current Method)

This is a multi-part message in MIME format. All, One of my colleagues in town has a question that he would like to post here, hoping to find an answer. If you have any thoughts, comments, or suggestions please reply with them, and I will forward them to him. Also, feel free to email Pete Va

[no subject]

Good People What is the basis of this formula for working voltage ? sqroot(a^2 + b^2) thanks, Brian

RE: NEBS Compliance

Hi Trevor, The NEBS levels are functionally defined as: * NEBS Level 1; the min acceptable level of environmental compatibility needed to preclude hazards and degradation of the network facility and hazards to personnel. Possible applications for Level 1 criteria include prototype equipmen

Re: CTL Decisions - the situation for Europe

Dear Gert, You say "CTL decisions are not relevant within the EC compliance system". I do not know what you mean by "EC compliance system" but if you mean that: 1) It is not necessary to comply with Harmonised Standards in order to claim compliance with the Safety Objectives of the LVD, or the

NEBS Compliance

Hi all, Is there anywhere I can find out what the NEBS Level 1, 2 & 3 requirements are. Obviously I can buy the Telcordia specs, but I just need a summary to understand what we actually have to aim for. Thanks, Trevor Chainey Telesoft Technologies Ltd.

RE: CTL Decisions - the situation for Europe

There is a similar situation here in the States. The United States Council of EMC Laboratories (USCEL) publishes consensus positions in the form of Technical Guidance Notes (TGNs). These TGNs, while not mandatory, provide a common perspective and clarification on domestic and International EMC is

RE: CTL Decisions - the situation for Europe

Group, CTL decisions are not relevant within the EC compliance system. Whether a manufacturer chooses to declare compliance based or not based on a CTL decision is simply not relevant as long as a compliance justification falls within a harmonised standard. If a test method can be carried

Re: CTL Decisions - the situation for Europe

John, Glad to see that you have started a new thread so that we may start afresh. In fact, in an earlier reply to Art Michael I did make a passing reference to OSM decisions relating to EN 60950. However, this may have been too brief or obscure for you to notice. Although I have never worked in

Re: CTL Decisions - the situation for Europe

I read in !emc-pstc that John Allen wrote (in ) about 'CTL Decisions - the situation for Europe' on Thu, 18 Dec 2003: >There appears to be a very serious issue if a CTL decision exists and is >signed up to by one or more EU test house - but is not published as a >common deviation in the releva

Re: CTL Decisions (was: RE: MOV's to ground)

I read in !emc-pstc that Arthur Michael wrote (in ) about 'CTL Decisions (was: RE: MOV's to ground)' on Wed, 17 Dec 2003: >In my experience, the CTL Decisions are not 'normative' but are a >consensus position arrived at by the CTL (Committee of Testing Labs). > >To my knowledge, the test labs ar

RE: CTL Decisions - the situation for Europe

Richard I do realise that you are probably correct in suggesting that we close the general thread at this point, but I do also want to raise one additional issue related to Europe & CENELEC which I cannot see having been addressed: There appears to be a very serious issue if a CTL decision exis

Alarm at 868-870 MHz

Hi All I have a alarm system working in the range 868-870 MHz, I want to apply for FCC by making use of 15.231, however someone told me that 868-870MHz is for AMPS and GSM only, it cannot be used for other applications. I would like to check if there is any document to say that this range is for