Re: [PSES] LISN Calibration Measurement Uncertainty

[Mac Elliott]

All, 
As always - thanks for the feedback and discussion. Learn a lot from this forum 
Best regards, 
Mac

  From: Ken Javor <ken.ja...@emccompliance.com>
 To: EMC-PSTC@LISTSERV.IEEE.ORG 
 Sent: Wednesday, September 13, 2017 8:57 AM
 Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
   
I assumed that since uncertainty was in question, that this was some sort of
CISPR 22 or similar quest, so 150 kHz and up, and not CISPR 25. If it were
CISPR 25, then it is a low impedance at 150 kHz as Tom points out, but using
the technique I suggested, excellent accuracy may still be had.

Ken Javor
Phone: (256) 650-5261



> From: "T.Sato" <vef00...@nifty.com>
> Reply-To: "T.Sato" <vef00...@nifty.com>
> Date: Wed, 13 Sep 2017 22:09:36 +0900
> To: <EMC-PSTC@LISTSERV.IEEE.ORG>
> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
> 
> On Tue, 12 Sep 2017 10:13:26 -0500,
>  Ken Javor <ken.ja...@emccompliance.com> wrote:
> 
>> There shouldn't be a lower impedance issue, because from 150 kHz up the LISN
>> is very close to 50 ohms.  And once the LISN coil impedance is well above 50
>> ohms, the measured LISN impedance should be 50 ohms in parallel with the
>> bleeder resistor, which is essentially 50 ohms. The only affect is if there
> ...
> 
> I think:
> 
>  o 50 ohms / 50 uH + 5 ohms LISN has impedance spec down to 9 kHz,
>    and its EUT port impedance is 5 ohms + j2.8 ohms at 9 kHz.
> 
>  o Automotive 5 uH LISN has impedance spec down to 150 kHz, and its
>    EUT port impedance is j4.7 ohms at 150 kHz.
> 
> Regards,
> Tom
> 
> -- 
> Tomonori Sato  <vef00...@nifty.com>
> URL: http://t-sato.in.coocan.jp
> 
> 
>>> From: "T.Sato" <vef00...@nifty.com>
>>> Reply-To: "T.Sato" <vef00...@nifty.com>
>>> Date: Tue, 12 Sep 2017 21:58:54 +0900
>>> To: <EMC-PSTC@LISTSERV.IEEE.ORG>
>>> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
>>> 
>>> On Mon, 11 Sep 2017 16:32:09 +,
>>>  Mac Elliott <0a115b29e815-dmarc-requ...@ieee.org> wrote:
>>> 
>>>> We are interested in doing some in-house LISN calibrations (impedance
>>>> verification only using network analyzer) and need to develop an
>>>> uncertainty
>>>> budget. 
>>>> Does anyone happen to have a budget you could share with us? We will go
>>>> through the exercise of calculating ourself but if there is one out there
>>>> would appreciate it if you could share.
>>> 
>>> I think the major contributions would be:
>>> 
>>>  o network analyzer (VNA?);
>>>  o calibration jig which will be required to connect coax to the LISN
>>> terminals.
>>> 
>>> Other possible contributions such as resolution and repeatability may also
>>> need to be considered, even if they are relatively minor.
>>> 
>>> 
>>> For lower impedance, network analyzers may have relatively large impedance
>>> measurement uncertainty:
>>> 
>>>  
>>> http://www.keysight.com/main/editorial.jspx?cc=ES=spa=102148:eps
>>> g:
>>> faq=-11143.0.00=102148:epsg:faq
>>> 
>>> Regards,
>>> Tom
>>> 
>>> -- 
>>> Tomonori Sato  <vef00...@nifty.com>
>>> URL: http://t-sato.in.coocan.jp
>>> 
>>> -
>>> 
>>> This message is from the IEEE Product Safety Engineering Society emc-pstc
>>> discussion list. To post a message to the list, send your e-mail to
>>> <emc-p...@ieee.org>
>>> 
>>> All emc-pstc postings are archived and searchable on the web at:
>>> http://www.ieee-pses.org/emc-pstc.html
>>> 
>>> Attachments are not permitted but the IEEE PSES Online Communities site at
>>> http://product-compliance.oc.ieee.org/ can be used for graphics (in
>>> well-used
>>> formats), large files, etc.
>>> 
>>> Website:  http://www.ieee-pses.org/
>>> Instructions:  http://www.ieee-pses.org/list.html (including how to
>>> unsubscribe)
>>> List rules: http://www.ieee-pses.org/listrules.html
>>> 
>>> For help, send mail to the list administrators:
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>>> Mike Cantwell <mcantw...@ieee.org>
>>> 
>>> For policy questions, send mail to:
>>> Jim Bacher:  <j.bac...@ieee.org>
>>> David Heald: <dhe...@gmail.com>
>> 
>> -
>> ---

Re: [PSES] LISN Calibration Measurement Uncertainty

[Ken Javor]

I assumed that since uncertainty was in question, that this was some sort of
CISPR 22 or similar quest, so 150 kHz and up, and not CISPR 25. If it were
CISPR 25, then it is a low impedance at 150 kHz as Tom points out, but using
the technique I suggested, excellent accuracy may still be had.

Ken Javor
Phone: (256) 650-5261



> From: "T.Sato" <vef00...@nifty.com>
> Reply-To: "T.Sato" <vef00...@nifty.com>
> Date: Wed, 13 Sep 2017 22:09:36 +0900
> To: <EMC-PSTC@LISTSERV.IEEE.ORG>
> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
> 
> On Tue, 12 Sep 2017 10:13:26 -0500,
>   Ken Javor <ken.ja...@emccompliance.com> wrote:
> 
>> There shouldn't be a lower impedance issue, because from 150 kHz up the LISN
>> is very close to 50 ohms.  And once the LISN coil impedance is well above 50
>> ohms, the measured LISN impedance should be 50 ohms in parallel with the
>> bleeder resistor, which is essentially 50 ohms. The only affect is if there
> ...
> 
> I think:
> 
>   o 50 ohms / 50 uH + 5 ohms LISN has impedance spec down to 9 kHz,
> and its EUT port impedance is 5 ohms + j2.8 ohms at 9 kHz.
> 
>   o Automotive 5 uH LISN has impedance spec down to 150 kHz, and its
> EUT port impedance is j4.7 ohms at 150 kHz.
> 
> Regards,
> Tom
> 
> -- 
> Tomonori Sato  <vef00...@nifty.com>
> URL: http://t-sato.in.coocan.jp
> 
> 
>>> From: "T.Sato" <vef00...@nifty.com>
>>> Reply-To: "T.Sato" <vef00...@nifty.com>
>>> Date: Tue, 12 Sep 2017 21:58:54 +0900
>>> To: <EMC-PSTC@LISTSERV.IEEE.ORG>
>>> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
>>> 
>>> On Mon, 11 Sep 2017 16:32:09 +,
>>>   Mac Elliott <0a115b29e815-dmarc-requ...@ieee.org> wrote:
>>> 
>>>> We are interested in doing some in-house LISN calibrations (impedance
>>>> verification only using network analyzer) and need to develop an
>>>> uncertainty
>>>> budget. 
>>>> Does anyone happen to have a budget you could share with us? We will go
>>>> through the exercise of calculating ourself but if there is one out there
>>>> would appreciate it if you could share.
>>> 
>>> I think the major contributions would be:
>>> 
>>>   o network analyzer (VNA?);
>>>   o calibration jig which will be required to connect coax to the LISN
>>> terminals.
>>> 
>>> Other possible contributions such as resolution and repeatability may also
>>> need to be considered, even if they are relatively minor.
>>> 
>>> 
>>> For lower impedance, network analyzers may have relatively large impedance
>>> measurement uncertainty:
>>> 
>>>   
>>> http://www.keysight.com/main/editorial.jspx?cc=ES=spa=102148:eps
>>> g:
>>> faq=-11143.0.00=102148:epsg:faq
>>> 
>>> Regards,
>>> Tom
>>> 
>>> -- 
>>> Tomonori Sato  <vef00...@nifty.com>
>>> URL: http://t-sato.in.coocan.jp
>>> 
>>> -
>>> 
>>> This message is from the IEEE Product Safety Engineering Society emc-pstc
>>> discussion list. To post a message to the list, send your e-mail to
>>> <emc-p...@ieee.org>
>>> 
>>> All emc-pstc postings are archived and searchable on the web at:
>>> http://www.ieee-pses.org/emc-pstc.html
>>> 
>>> Attachments are not permitted but the IEEE PSES Online Communities site at
>>> http://product-compliance.oc.ieee.org/ can be used for graphics (in
>>> well-used
>>> formats), large files, etc.
>>> 
>>> Website:  http://www.ieee-pses.org/
>>> Instructions:  http://www.ieee-pses.org/list.html (including how to
>>> unsubscribe)
>>> List rules: http://www.ieee-pses.org/listrules.html
>>> 
>>> For help, send mail to the list administrators:
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>>> Mike Cantwell <mcantw...@ieee.org>
>>> 
>>> For policy questions, send mail to:
>>> Jim Bacher:  <j.bac...@ieee.org>
>>> David Heald: <dhe...@gmail.com>
>> 
>> -
>> 
>> This message is from the IEEE Product Safety Engineering Society emc-pstc
>> discussion list. To post a message to the list, send your e-mail to
>> <emc-p...@ieee.org>
>> 
>> All emc-pstc postings are archived and searchabl

Re: [PSES] LISN Calibration Measurement Uncertainty

[T.Sato]

On Tue, 12 Sep 2017 10:13:26 -0500,
  Ken Javor <ken.ja...@emccompliance.com> wrote:

> There shouldn't be a lower impedance issue, because from 150 kHz up the LISN
> is very close to 50 ohms.  And once the LISN coil impedance is well above 50
> ohms, the measured LISN impedance should be 50 ohms in parallel with the
> bleeder resistor, which is essentially 50 ohms. The only affect is if there
...

I think:

  o 50 ohms / 50 uH + 5 ohms LISN has impedance spec down to 9 kHz,
and its EUT port impedance is 5 ohms + j2.8 ohms at 9 kHz.

  o Automotive 5 uH LISN has impedance spec down to 150 kHz, and its
EUT port impedance is j4.7 ohms at 150 kHz.

Regards,
Tom

-- 
Tomonori Sato  <vef00...@nifty.com>
URL: http://t-sato.in.coocan.jp


>> From: "T.Sato" <vef00...@nifty.com>
>> Reply-To: "T.Sato" <vef00...@nifty.com>
>> Date: Tue, 12 Sep 2017 21:58:54 +0900
>> To: <EMC-PSTC@LISTSERV.IEEE.ORG>
>> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
>> 
>> On Mon, 11 Sep 2017 16:32:09 +,
>>   Mac Elliott <0a115b29e815-dmarc-requ...@ieee.org> wrote:
>> 
>>> We are interested in doing some in-house LISN calibrations (impedance
>>> verification only using network analyzer) and need to develop an uncertainty
>>> budget. 
>>> Does anyone happen to have a budget you could share with us? We will go
>>> through the exercise of calculating ourself but if there is one out there
>>> would appreciate it if you could share.
>> 
>> I think the major contributions would be:
>> 
>>   o network analyzer (VNA?);
>>   o calibration jig which will be required to connect coax to the LISN
>> terminals.
>> 
>> Other possible contributions such as resolution and repeatability may also
>> need to be considered, even if they are relatively minor.
>> 
>> 
>> For lower impedance, network analyzers may have relatively large impedance
>> measurement uncertainty:
>> 
>>   
>> http://www.keysight.com/main/editorial.jspx?cc=ES=spa=102148:epsg:
>> faq=-11143.0.00=102148:epsg:faq
>> 
>> Regards,
>> Tom
>> 
>> -- 
>> Tomonori Sato  <vef00...@nifty.com>
>> URL: http://t-sato.in.coocan.jp
>> 
>> -
>> 
>> This message is from the IEEE Product Safety Engineering Society emc-pstc
>> discussion list. To post a message to the list, send your e-mail to
>> <emc-p...@ieee.org>
>> 
>> All emc-pstc postings are archived and searchable on the web at:
>> http://www.ieee-pses.org/emc-pstc.html
>> 
>> Attachments are not permitted but the IEEE PSES Online Communities site at
>> http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used
>> formats), large files, etc.
>> 
>> Website:  http://www.ieee-pses.org/
>> Instructions:  http://www.ieee-pses.org/list.html (including how to
>> unsubscribe)
>> List rules: http://www.ieee-pses.org/listrules.html
>> 
>> For help, send mail to the list administrators:
>> Scott Douglas <sdoug...@ieee.org>
>> Mike Cantwell <mcantw...@ieee.org>
>> 
>> For policy questions, send mail to:
>> Jim Bacher:  <j.bac...@ieee.org>
>> David Heald: <dhe...@gmail.com>
> 
> -
> 
> This message is from the IEEE Product Safety Engineering Society emc-pstc 
> discussion list. To post a message to the list, send your e-mail to 
> <emc-p...@ieee.org>
> 
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
> 
> Attachments are not permitted but the IEEE PSES Online Communities site at 
> http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
> formats), large files, etc.
> 
> Website:  http://www.ieee-pses.org/
> Instructions:  http://www.ieee-pses.org/list.html (including how to 
> unsubscribe)
> List rules: http://www.ieee-pses.org/listrules.html
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> For help, send mail to the list administrators:
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> Mike Cantwell <mcantw...@ieee.org>
> 
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> David Heald: <dhe...@gmail.com>

-

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Re: [PSES] LISN Calibration Measurement Uncertainty

[Ken Javor]

There shouldn't be a lower impedance issue, because from 150 kHz up the LISN
is very close to 50 ohms.  And once the LISN coil impedance is well above 50
ohms, the measured LISN impedance should be 50 ohms in parallel with the
bleeder resistor, which is essentially 50 ohms. The only affect is if there
is a parasitic that tanks with the coil to lower the total impedance to
something closer to 50 ohms. That shouldn't be the case down the road if not
when acquired, unless the LISN is damaged.  So there really shouldn't be an
issue here. Also, not familiar with modern VNAs (my HP 4195A has a max
output of 15 dBm, or 122 dBuV across 50 ohms), but if I were using a signal
generator and a spectrum analyzer, I could use quite high potentials (3
volts or more) and very flat current probe with say 0.1 or 1 ohm transfer
impedance, to get numbers well above my noise floor, and a current probe
with flat and low transfer impedance is very accurate because the value
depends not on the construction of the probe but on the loading resistance,
which is much easier to get to a specific value, just like the 50 ohms of
the LISN has been noted in this thread to not be part of the LISN
construction, but the load placed on it by a spectrum analyze or a dummy
load of great precision.  And the spectrum analyzer as a load must have at
least 10 dB internal or external attenuation selected in order to give
assurance that it looks like 50 ohms.

Ken Javor
Phone: (256) 650-5261



> From: "T.Sato" <vef00...@nifty.com>
> Reply-To: "T.Sato" <vef00...@nifty.com>
> Date: Tue, 12 Sep 2017 21:58:54 +0900
> To: <EMC-PSTC@LISTSERV.IEEE.ORG>
> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
> 
> On Mon, 11 Sep 2017 16:32:09 +,
>   Mac Elliott <0a115b29e815-dmarc-requ...@ieee.org> wrote:
> 
>> We are interested in doing some in-house LISN calibrations (impedance
>> verification only using network analyzer) and need to develop an uncertainty
>> budget. 
>> Does anyone happen to have a budget you could share with us? We will go
>> through the exercise of calculating ourself but if there is one out there
>> would appreciate it if you could share.
> 
> I think the major contributions would be:
> 
>   o network analyzer (VNA?);
>   o calibration jig which will be required to connect coax to the LISN
> terminals.
> 
> Other possible contributions such as resolution and repeatability may also
> need to be considered, even if they are relatively minor.
> 
> 
> For lower impedance, network analyzers may have relatively large impedance
> measurement uncertainty:
> 
>   
> http://www.keysight.com/main/editorial.jspx?cc=ES=spa=102148:epsg:
> faq=-11143.0.00=102148:epsg:faq
> 
> Regards,
> Tom
> 
> -- 
> Tomonori Sato  <vef00...@nifty.com>
> URL: http://t-sato.in.coocan.jp
> 
> -
> 
> This message is from the IEEE Product Safety Engineering Society emc-pstc
> discussion list. To post a message to the list, send your e-mail to
> <emc-p...@ieee.org>
> 
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
> 
> Attachments are not permitted but the IEEE PSES Online Communities site at
> http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used
> formats), large files, etc.
> 
> Website:  http://www.ieee-pses.org/
> Instructions:  http://www.ieee-pses.org/list.html (including how to
> unsubscribe)
> List rules: http://www.ieee-pses.org/listrules.html
> 
> For help, send mail to the list administrators:
> Scott Douglas <sdoug...@ieee.org>
> Mike Cantwell <mcantw...@ieee.org>
> 
> For policy questions, send mail to:
> Jim Bacher:  <j.bac...@ieee.org>
> David Heald: <dhe...@gmail.com>

-

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Re: [PSES] LISN Calibration Measurement Uncertainty

[T.Sato]

On Mon, 11 Sep 2017 16:32:09 +,
  Mac Elliott <0a115b29e815-dmarc-requ...@ieee.org> wrote:

> We are interested in doing some in-house LISN calibrations (impedance 
> verification only using network analyzer) and need to develop an uncertainty 
> budget. 
> Does anyone happen to have a budget you could share with us? We will go 
> through the exercise of calculating ourself but if there is one out there 
> would appreciate it if you could share.

I think the major contributions would be:

  o network analyzer (VNA?);
  o calibration jig which will be required to connect coax to the LISN 
terminals.

Other possible contributions such as resolution and repeatability may also need 
to be considered, even if they are relatively minor.


For lower impedance, network analyzers may have relatively large impedance 
measurement uncertainty:

  
http://www.keysight.com/main/editorial.jspx?cc=ES=spa=102148:epsg:faq=-11143.0.00=102148:epsg:faq

Regards,
Tom

-- 
Tomonori Sato  
URL: http://t-sato.in.coocan.jp

-

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Re: [PSES] LISN Calibration Measurement Uncertainty

[John Woodgate]

I'm afraid that one cannot assume that our ancestors were either all-knowing
or idiots. They were people, just like us, and they got it right mostly, but
not always.

With best wishes DESIGN IT IN! OOO - Own Opinions Only
www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England

UK is a sovereignty, not a Zollverein-ty

-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com] 
Sent: Tuesday, September 12, 2017 12:37 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

Perhaps all that is needed is to know is the Insertion Loss of the LISN.
Some manufacturers provide this for every s/n.

The LISN is only there to provide a known impedance to the source of
emission so that RF current can be measured with  repeatability.  I do
understand that CM and DM currents will have different (and unknown) source
impedance and that those impedances will be a function of frequency, but I
feel that's beside the point.  

I have to assume the folks at CISPR understood those topics and that they
likely deliberated long and hard and did lots of measurements both in the
lab and in the field before agreeing on the LISN as a standard transducer
for the evaluation of conducted RF emission.

If there were something fundamentally wrong with the method of measurement,
I suspect it would have been uncovered long ago.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Monday, September 11, 2017 4:10 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

The point of the cm vs. dm discussion is that the effect of LISN impedance
is not so important for dm as for cm, speaking very generally, so that the
effect of uncertainty in LISN impedance on dm emissions is less than for cm.
But we don't separately measure cm and dm, so we don't know, looking at any
specific signal, what the uncertainty is, even if we have nailed down the
uncertainty of the LISN impedance. And you don't need two LISNs to separate
modes, but that is another discussion.


Ken Javor
Phone: (256) 650-5261

-

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Re: [PSES] LISN Calibration Measurement Uncertainty

[Ken Javor]

No criticism of how a LISN is calibrated.  That wasn't the point. The point
was that LISN impedance uncertainty affects the measurement of conducted
emissions differently by mode, so that the overall uncertainty of the
measurement of CE is different from that of the LISN impedance. Also, while
the point of a 50 uH LISN is in fact to provide that impedance, the original
limit was based on the rf susceptibility of radios operating below 30 MHz,
and that susceptibility was to the rf potential caused by various electronic
loads. It wasn't about current at all.

Ken Javor
Phone: (256) 650-5261



> From: Ralph McDiarmid <ralph.mcdiar...@schneider-electric.com>
> Date: Mon, 11 Sep 2017 23:36:35 +
> To: Ken Javor <ken.ja...@emccompliance.com>, "EMC-PSTC@LISTSERV.IEEE.ORG"
> <EMC-PSTC@LISTSERV.IEEE.ORG>
> Conversation: [PSES] LISN Calibration Measurement Uncertainty
> Subject: RE: [PSES] LISN Calibration Measurement Uncertainty
> 
> Perhaps all that is needed is to know is the Insertion Loss of the LISN.  Some
> manufacturers provide this for every s/n.
> 
> The LISN is only there to provide a known impedance to the source of emission
> so that RF current can be measured with  repeatability.  I do understand that
> CM and DM currents will have different (and unknown) source impedance and that
> those impedances will be a function of frequency, but I feel that's beside the
> point.  
> 
> I have to assume the folks at CISPR understood those topics and that they
> likely deliberated long and hard and did lots of measurements both in the lab
> and in the field before agreeing on the LISN as a standard transducer for the
> evaluation of conducted RF emission.
> 
> If there were something fundamentally wrong with the method of measurement, I
> suspect it would have been uncovered long ago.
> 
> Ralph McDiarmid
> Product Compliance
> Engineering
> Solar Business
> Schneider Electric
> 
> 
> From: Ken Javor [mailto:ken.ja...@emccompliance.com]
> Sent: Monday, September 11, 2017 4:10 PM
> To: EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
> 
> The point of the cm vs. dm discussion is that the effect of LISN impedance is
> not so important for dm as for cm, speaking very generally, so that the effect
> of uncertainty in LISN impedance on dm emissions is less than for cm. But we
> don't separately measure cm and dm, so we don't know, looking at any specific
> signal, what the uncertainty is, even if we have nailed down the uncertainty
> of the LISN impedance. And you don't need two LISNs to separate modes, but
> that is another discussion.
> 
> 
> Ken Javor
> Phone: (256) 650-5261
> 

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
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<emc-p...@ieee.org>

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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

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Re: [PSES] LISN Calibration Measurement Uncertainty

[Ralph McDiarmid]

Perhaps all that is needed is to know is the Insertion Loss of the LISN.  Some 
manufacturers provide this for every s/n.

The LISN is only there to provide a known impedance to the source of emission 
so that RF current can be measured with  repeatability.  I do understand that 
CM and DM currents will have different (and unknown) source impedance and that 
those impedances will be a function of frequency, but I feel that's beside the 
point.  

I have to assume the folks at CISPR understood those topics and that they 
likely deliberated long and hard and did lots of measurements both in the lab 
and in the field before agreeing on the LISN as a standard transducer for the 
evaluation of conducted RF emission.

If there were something fundamentally wrong with the method of measurement, I 
suspect it would have been uncovered long ago.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Ken Javor [mailto:ken.ja...@emccompliance.com] 
Sent: Monday, September 11, 2017 4:10 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

The point of the cm vs. dm discussion is that the effect of LISN impedance is 
not so important for dm as for cm, speaking very generally, so that the effect 
of uncertainty in LISN impedance on dm emissions is less than for cm. But we 
don't separately measure cm and dm, so we don't know, looking at any specific 
signal, what the uncertainty is, even if we have nailed down the uncertainty of 
the LISN impedance. And you don't need two LISNs to separate modes, but that is 
another discussion.


Ken Javor
Phone: (256) 650-5261

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
<emc-p...@ieee.org>

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
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List rules: http://www.ieee-pses.org/listrules.html

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Mike Cantwell <mcantw...@ieee.org>

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Jim Bacher:  <j.bac...@ieee.org>
David Heald: <dhe...@gmail.com>

Re: [PSES] LISN Calibration Measurement Uncertainty

[Ken Javor]

The point of the cm vs. dm discussion is that the effect of LISN impedance
is not so important for dm as for cm, speaking very generally, so that the
effect of uncertainty in LISN impedance on dm emissions is less than for cm.
But we don't separately measure cm and dm, so we don't know, looking at any
specific signal, what the uncertainty is, even if we have nailed down the
uncertainty of the LISN impedance. And you don't need two LISNs to separate
modes, but that is another discussion.




Ken Javor
Phone: (256) 650-5261


> From: Ralph McDiarmid <ralph.mcdiar...@schneider-electric.com>
> Reply-To: Ralph McDiarmid <ralph.mcdiar...@schneider-electric.com>
> Date: Mon, 11 Sep 2017 22:32:14 +
> To: <EMC-PSTC@LISTSERV.IEEE.ORG>
> Conversation: [PSES] LISN Calibration Measurement Uncertainty
> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
> 
> Sorry, I guess we drifted a little off topic, and that's my fault.  If you
> want to characterize a LISN for the purpose of defining an measurement
> "uncertainty budget" then I suppose all that is needed is a carefully written
> test procedure.  I doubt a Network Analyzer is required, I think a signal
> generator and a scope would suffice.
> 
> What parameter of a LISN matters for determining its measurement uncertainty?
> I can only think of the impedance "seen"  the DUT.  As the impedance gradually
> moves away from the ideal 50 ohm resistive, then I think less signal reaches
> the EMI receiver, and that is the "uncertainty" or maybe error is a better
> term.  I really cannot see how CM vs DM comes into play at all; the LISN
> measures both as far as I know, so one cannot separate the two, without using
> a second LISN connected to a second power pole of the DUT.  I think save to
> say that most DUTs will have a least two power poles, a "line" and a "neutral
> for connection to the a.c. mains.
> 
> I think some manufactures provide a graph or two plotting something (perhaps
> insertion loss versus frequency) for that serial number.
> 
> I hope that helped a little.
> 
> Ralph McDiarmid
> Product Compliance
> Engineering
> Solar Business
> Schneider Electric
> 
> 
> -Original Message-
> From: John Woodgate [mailto:jmw1...@btinternet.com]
> Sent: Monday, September 11, 2017 1:28 PM
> To: Ralph McDiarmid <ralph.mcdiar...@schneider-electric.com>;
> EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: RE: [PSES] LISN Calibration Measurement Uncertainty
> 
> It's not quite as simple as it may appear. Mr Javor points out that it
> measures two mixtures of DM and CM voltages, which is not helpful either in
> fixing a design or in determining the consequent radiated emission (due to the
> CM component alone).
> 
> The 50 ohms is indeed the input resistance of the SA. But it's not necessarily
> (not likely to be) the impedance looking back down the mains lead to the EUT.
> All it does is to help produce consistent results, it doesn't do anything to
> help the results to be representative of real world conditions.
> 
> With best wishes DESIGN IT IN! OOO - Own Opinions Only www.jmwa.demon.co.uk J
> M Woodgate and Associates Rayleigh England
> 
> UK is a sovereignty, not a Zollverein-ty
> 
> -Original Message-
> From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com]
> Sent: Monday, September 11, 2017 7:33 PM
> To: EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: Re: [PSES] LISN Calibration Measurement Uncertainty
> 
> My understanding:
> 
> A LISN seems to be a simple device, which has three ports: an input, an
> output, and a sense port.  The sense port connects to the spectrum analyzer or
> EMI receiver, with the input port connecting to mains, and the output port
> connecting to the power terminals of the device under test (DUT).
> 
> What impedance is important?  I assume it is that impedance which is "seen"
> by the DUT when it is connected to the output port of the LISN.  I think it is
> that impedance which is 'stabilized' over a given bandwidth for the purpose of
> a repeatable measurement environment.
> 
> When we talk about a "50 ohm LISN", isn't it the EMI receiver that provides
> the 50 ohms? Both above and below the design bandwidth of the LISN (AMN),
> there will be reactance (inductive or capacitive) that begins to affect the
> impedance seen by the DUT, which moves the load impedance further away from
> the ideal 50 ohms.
> 
> 
> Ralph McDiarmid
> Product Compliance
> Engineering
> Solar Business
> Schneider Electric
> 
> 
> From: Ken Javor [mailto:ken.ja...@emccompliance.com]
> Sent: Monday, September 11, 2017 10:21 AM
> To: EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: Re: [PSES

Re: [PSES] LISN Calibration Measurement Uncertainty

[Ralph McDiarmid]

Sorry, I guess we drifted a little off topic, and that's my fault.  If you want 
to characterize a LISN for the purpose of defining an measurement "uncertainty 
budget" then I suppose all that is needed is a carefully written test 
procedure.  I doubt a Network Analyzer is required, I think a signal generator 
and a scope would suffice.

What parameter of a LISN matters for determining its measurement uncertainty?  
I can only think of the impedance "seen"  the DUT.  As the impedance gradually 
moves away from the ideal 50 ohm resistive, then I think less signal reaches 
the EMI receiver, and that is the "uncertainty" or maybe error is a better 
term.  I really cannot see how CM vs DM comes into play at all; the LISN 
measures both as far as I know, so one cannot separate the two, without using a 
second LISN connected to a second power pole of the DUT.  I think save to say 
that most DUTs will have a least two power poles, a "line" and a "neutral for 
connection to the a.c. mains.

I think some manufactures provide a graph or two plotting something (perhaps 
insertion loss versus frequency) for that serial number.

I hope that helped a little.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: John Woodgate [mailto:jmw1...@btinternet.com] 
Sent: Monday, September 11, 2017 1:28 PM
To: Ralph McDiarmid <ralph.mcdiar...@schneider-electric.com>; 
EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] LISN Calibration Measurement Uncertainty

It's not quite as simple as it may appear. Mr Javor points out that it measures 
two mixtures of DM and CM voltages, which is not helpful either in fixing a 
design or in determining the consequent radiated emission (due to the CM 
component alone).

The 50 ohms is indeed the input resistance of the SA. But it's not necessarily 
(not likely to be) the impedance looking back down the mains lead to the EUT. 
All it does is to help produce consistent results, it doesn't do anything to 
help the results to be representative of real world conditions.

With best wishes DESIGN IT IN! OOO - Own Opinions Only www.jmwa.demon.co.uk J M 
Woodgate and Associates Rayleigh England

UK is a sovereignty, not a Zollverein-ty

-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com]
Sent: Monday, September 11, 2017 7:33 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

My understanding:

A LISN seems to be a simple device, which has three ports: an input, an output, 
and a sense port.  The sense port connects to the spectrum analyzer or EMI 
receiver, with the input port connecting to mains, and the output port 
connecting to the power terminals of the device under test (DUT). 

What impedance is important?  I assume it is that impedance which is "seen"
by the DUT when it is connected to the output port of the LISN.  I think it is 
that impedance which is 'stabilized' over a given bandwidth for the purpose of 
a repeatable measurement environment.  

When we talk about a "50 ohm LISN", isn't it the EMI receiver that provides the 
50 ohms? Both above and below the design bandwidth of the LISN (AMN), there 
will be reactance (inductive or capacitive) that begins to affect the impedance 
seen by the DUT, which moves the load impedance further away from the ideal 50 
ohms.  


Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Monday, September 11, 2017 10:21 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

Off-topic response. Grinding an axe.  Clearly the network analyzer itself 
serves as a limit on the achievable uncertainty, but it should be much better 
than what is needed (+/-20% in the military world).  That aside, consider that 
differential mode emissions tend to be low impedance relative to that of the 
LISN, and therefore act as voltage sources, whose amplitude doesn't correspond 
much to changes in LISN amplitude.  Common mode emissions tend to be current 
sources and therefore common mode emission amplitudes track closely with 
changes in LISN impedance.  But we don't measure these modes separately, but 
rather as vector sums on the phase conductor, and vector differences on 
neutral, so we have no idea what the effect of the LISN impedance on any 
particular emission measured actually is.

Ken Javor
Phone: (256) 650-5261


From: Mac Elliott <mailto:0a115b29e815-dmarc-requ...@ieee.org>
Reply-To: Mac Elliott <mailto:mac_elli...@yahoo.com>
Date: Mon, 11 Sep 2017 16:32:09 +
To: <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>
Subject: [PSES] LISN Calibration Measurement Uncertainty

All, 

We are interested in doing some in-house LISN calibrations (impedance 
verification only

Re: [PSES] LISN Calibration Measurement Uncertainty

[Ralph McDiarmid]

I agree that the AMN (LISN) is intended only to provide consistent (more or 
less) results, not to represent a real-world impedance at RF.  I don't know how 
much that impedance changes from site to site;  quite a lot I'll bet.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: John Woodgate [mailto:jmw1...@btinternet.com] 
Sent: Monday, September 11, 2017 1:28 PM
To: Ralph McDiarmid <ralph.mcdiar...@schneider-electric.com>; 
EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] LISN Calibration Measurement Uncertainty

It's not quite as simple as it may appear. Mr Javor points out that it measures 
two mixtures of DM and CM voltages, which is not helpful either in fixing a 
design or in determining the consequent radiated emission (due to the CM 
component alone).

The 50 ohms is indeed the input resistance of the SA. But it's not necessarily 
(not likely to be) the impedance looking back down the mains lead to the EUT. 
All it does is to help produce consistent results, it doesn't do anything to 
help the results to be representative of real world conditions.

With best wishes DESIGN IT IN! OOO - Own Opinions Only www.jmwa.demon.co.uk J M 
Woodgate and Associates Rayleigh England

UK is a sovereignty, not a Zollverein-ty

-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com]
Sent: Monday, September 11, 2017 7:33 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

My understanding:

A LISN seems to be a simple device, which has three ports: an input, an output, 
and a sense port.  The sense port connects to the spectrum analyzer or EMI 
receiver, with the input port connecting to mains, and the output port 
connecting to the power terminals of the device under test (DUT). 

What impedance is important?  I assume it is that impedance which is "seen"
by the DUT when it is connected to the output port of the LISN.  I think it is 
that impedance which is 'stabilized' over a given bandwidth for the purpose of 
a repeatable measurement environment.  

When we talk about a "50 ohm LISN", isn't it the EMI receiver that provides the 
50 ohms? Both above and below the design bandwidth of the LISN (AMN), there 
will be reactance (inductive or capacitive) that begins to affect the impedance 
seen by the DUT, which moves the load impedance further away from the ideal 50 
ohms.  


Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Monday, September 11, 2017 10:21 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

Off-topic response. Grinding an axe.  Clearly the network analyzer itself 
serves as a limit on the achievable uncertainty, but it should be much better 
than what is needed (+/-20% in the military world).  That aside, consider that 
differential mode emissions tend to be low impedance relative to that of the 
LISN, and therefore act as voltage sources, whose amplitude doesn't correspond 
much to changes in LISN amplitude.  Common mode emissions tend to be current 
sources and therefore common mode emission amplitudes track closely with 
changes in LISN impedance.  But we don't measure these modes separately, but 
rather as vector sums on the phase conductor, and vector differences on 
neutral, so we have no idea what the effect of the LISN impedance on any 
particular emission measured actually is.

Ken Javor
Phone: (256) 650-5261


From: Mac Elliott <mailto:0a115b29e815-dmarc-requ...@ieee.org>
Reply-To: Mac Elliott <mailto:mac_elli...@yahoo.com>
Date: Mon, 11 Sep 2017 16:32:09 +
To: <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>
Subject: [PSES] LISN Calibration Measurement Uncertainty

All, 

We are interested in doing some in-house LISN calibrations (impedance 
verification only using network analyzer) and need to develop an uncertainty 
budget. 

Does anyone happen to have a budget you could share with us? We will go through 
the exercise of calculating ourself but if there is one out there would 
appreciate it if you could share.

Have a great day

Mac Elliott
-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
<mailto:emc-p...@ieee.org>

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to
unsubscribe) http://www.ieee-pses.org/list.html
List 

Re: [PSES] LISN Calibration Measurement Uncertainty

[John Woodgate]

It's not quite as simple as it may appear. Mr Javor points out that it
measures two mixtures of DM and CM voltages, which is not helpful either in
fixing a design or in determining the consequent radiated emission (due to
the CM component alone).

The 50 ohms is indeed the input resistance of the SA. But it's not
necessarily (not likely to be) the impedance looking back down the mains
lead to the EUT. All it does is to help produce consistent results, it
doesn't do anything to help the results to be representative of real world
conditions.

With best wishes DESIGN IT IN! OOO – Own Opinions Only
www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England

UK is a sovereignty, not a Zollverein-ty

-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com] 
Sent: Monday, September 11, 2017 7:33 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

My understanding:

A LISN seems to be a simple device, which has three ports: an input, an
output, and a sense port.  The sense port connects to the spectrum analyzer
or EMI receiver, with the input port connecting to mains, and the output
port connecting to the power terminals of the device under test (DUT). 

What impedance is important?  I assume it is that impedance which is "seen"
by the DUT when it is connected to the output port of the LISN.  I think it
is that impedance which is 'stabilized' over a given bandwidth for the
purpose of a repeatable measurement environment.  

When we talk about a "50 ohm LISN", isn't it the EMI receiver that provides
the 50 ohms? Both above and below the design bandwidth of the LISN (AMN),
there will be reactance (inductive or capacitive) that begins to affect the
impedance seen by the DUT, which moves the load impedance further away from
the ideal 50 ohms.  


Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Monday, September 11, 2017 10:21 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

Off-topic response. Grinding an axe.  Clearly the network analyzer itself
serves as a limit on the achievable uncertainty, but it should be much
better than what is needed (+/-20% in the military world).  That aside,
consider that differential mode emissions tend to be low impedance relative
to that of the LISN, and therefore act as voltage sources, whose amplitude
doesn't correspond much to changes in LISN amplitude.  Common mode emissions
tend to be current sources and therefore common mode emission amplitudes
track closely with changes in LISN impedance.  But we don't measure these
modes separately, but rather as vector sums on the phase conductor, and
vector differences on neutral, so we have no idea what the effect of the
LISN impedance on any particular emission measured actually is.

Ken Javor
Phone: (256) 650-5261


From: Mac Elliott <mailto:0a115b29e815-dmarc-requ...@ieee.org>
Reply-To: Mac Elliott <mailto:mac_elli...@yahoo.com>
Date: Mon, 11 Sep 2017 16:32:09 +
To: <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>
Subject: [PSES] LISN Calibration Measurement Uncertainty

All, 

We are interested in doing some in-house LISN calibrations (impedance
verification only using network analyzer) and need to develop an uncertainty
budget. 

Does anyone happen to have a budget you could share with us? We will go
through the exercise of calculating ourself but if there is one out there
would appreciate it if you could share.

Have a great day

Mac Elliott
-


This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to
<mailto:emc-p...@ieee.org>

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at
http://product-compliance.oc.ieee.org/ can be used for graphics (in
well-used formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to
unsubscribe) http://www.ieee-pses.org/list.html
List rules: http://www.ieee-pses.org/listrules.html 

For help, send mail to the list administrators:
Scott Douglas <mailto:sdoug...@ieee.org> Mike Cantwell
<mailto:mcantw...@ieee.org> 

For policy questions, send mail to:
Jim Bacher  <mailto:j.bac...@ieee.org>
David Heald <mailto:dhe...@gmail.com> 


__
This email has been scanned by the Symantec Email Security.cloud service.
__
-

This message is 

Re: [PSES] LISN Calibration Measurement Uncertainty

[Ralph McDiarmid]

My understanding:

A LISN seems to be a simple device, which has three ports: an input, an output, 
and a sense port.  The sense port connects to the spectrum analyzer or EMI 
receiver, with the input port connecting to mains, and the output port 
connecting to the power terminals of the device under test (DUT). 

What impedance is important?  I assume it is that impedance which is "seen" by 
the DUT when it is connected to the output port of the LISN.  I think it is 
that impedance which is 'stabilized' over a given bandwidth for the purpose of 
a repeatable measurement environment.  

When we talk about a "50 ohm LISN", isn't it the EMI receiver that provides the 
50 ohms? Both above and below the design bandwidth of the LISN (AMN), there 
will be reactance (inductive or capacitive) that begins to affect the impedance 
seen by the DUT, which moves the load impedance further away from the ideal 50 
ohms.  


Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Ken Javor [mailto:ken.ja...@emccompliance.com] 
Sent: Monday, September 11, 2017 10:21 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LISN Calibration Measurement Uncertainty

Off-topic response. Grinding an axe.  Clearly the network analyzer itself 
serves as a limit on the achievable uncertainty, but it should be much better 
than what is needed (+/-20% in the military world).  That aside, consider that 
differential mode emissions tend to be low impedance relative to that of the 
LISN, and therefore act as voltage sources, whose amplitude doesn't correspond 
much to changes in LISN amplitude.  Common mode emissions tend to be current 
sources and therefore common mode emission amplitudes track closely with 
changes in LISN impedance.  But we don't measure these modes separately, but 
rather as vector sums on the phase conductor, and vector differences on 
neutral, so we have no idea what the effect of the LISN impedance on any 
particular emission measured actually is.

Ken Javor
Phone: (256) 650-5261


From: Mac Elliott <mailto:0a115b29e815-dmarc-requ...@ieee.org>
Reply-To: Mac Elliott <mailto:mac_elli...@yahoo.com>
Date: Mon, 11 Sep 2017 16:32:09 +
To: <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>
Subject: [PSES] LISN Calibration Measurement Uncertainty

All, 

We are interested in doing some in-house LISN calibrations (impedance 
verification only using network analyzer) and need to develop an uncertainty 
budget. 

Does anyone happen to have a budget you could share with us? We will go through 
the exercise of calculating ourself but if there is one out there would 
appreciate it if you could share.

Have a great day

Mac Elliott
-


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This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
<mailto:emc-p...@ieee.org>
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Re: [PSES] LISN Calibration Measurement Uncertainty

[Ken Javor]

Off-topic response. Grinding an axe.  Clearly the network analyzer itself
serves as a limit on the achievable uncertainty, but it should be much
better than what is needed (+/-20% in the military world).  That aside,
consider that differential mode emissions tend to be low impedance relative
to that of the LISN, and therefore act as voltage sources, whose amplitude
doesn¹t correspond much to changes in LISN amplitude.  Common mode emissions
tend to be current sources and therefore common mode emission amplitudes
track closely with changes in LISN impedance.  But we don¹t measure these
modes separately, but rather as vector sums on the phase conductor, and
vector differences on neutral, so we have no idea what the effect of the
LISN impedance on any particular emission measured actually is.

Ken Javor
Phone: (256) 650-5261



From: Mac Elliott <0a115b29e815-dmarc-requ...@ieee.org>
Reply-To: Mac Elliott 
Date: Mon, 11 Sep 2017 16:32:09 +
To: 
Subject: [PSES] LISN Calibration Measurement Uncertainty

All, 

We are interested in doing some in-house LISN calibrations (impedance
verification only using network analyzer) and need to develop an uncertainty
budget. 

Does anyone happen to have a budget you could share with us? We will go
through the exercise of calculating ourself but if there is one out there
would appreciate it if you could share.

Have a great day

Mac Elliott
-


This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at
http://product-compliance.oc.ieee.org/ can be used for graphics (in
well-used formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to
unsubscribe) 
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher  
David Heald 



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This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

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Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

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Jim Bacher:  
David Heald: