Thanks John. Can you tell me if "margins" are calculated into the limits?
It seems to me that reasonable people would do this.

Bob Heller
3M EMC Laboratory, 76-1-01
St. Paul, MN 55107-1208
Tel:  651- 778-6336
Fax:  651-778-6252
=========================


                                                                           
             John Woodgate                                                 
             <[email protected]                                             
             o.uk>                                                      To 
             Sent by:                  [email protected]                   
             [email protected]                                          cc 
                                                                           
                                                                   Subject 
             08/02/2005 03:18          Re: Request for info on CE Mark     
             AM                        penalties                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




[email protected] wrote (in
<of4dfcba4f.8b0f8edb-on86257051.002a7817-86257051.002af...@mmm.com>)
about 'Request for info on CE Mark penalties', on Tue, 2 Aug 2005:
>Dave, I have been trying for some time now to find out just exactly how
>limits lines were derived. Can you point me to a study/report/data that
>can show me (or more importantly, others here at work) just how the
>limits were derived? No one seems to be able to.

Derived from a mixture of experience, experiments and theoretical
studies. I meant what I said about setting the limits so as to reduce
interference complaints to an acceptable minimum. If the number of
complaints starts to increase, steps are taken to tighten the limits.

There is less motivation to relax limits if complaints fall to very low
levels, as may happen in Europe now that immunity is controlled.

You may find this helpful:

CISPR/TR 16-4-4 {Ed.1.0} Specification for radio disturbance and
immunity measuring apparatus and methods - Part 4-4: Uncertainties,
statistics and limit modelling - Statistics of complaints and a model
for the calculation of limits.

Note 'a model for the calculation of limits'.
--
Regards, John Woodgate, OOO - Own Opinions Only.
Deadlines are 90% of deadliness.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk


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