Geetha,
So the lesson is this:
1. In Europe, US & Japan even without a ferrite core your device will not
do any harm.
2. But in Taiwan if a ferrite core is not added in the USB cable it will
harm.
K.Balasubramanian
John Woodgate
<[email protected] To: Geetha
Balasubramanian <[email protected]>
> cc:
[email protected]
Sent by: Subject: Re: Radiated
Emission Testing
owner-emc-pstc@LISTSE
RV.IEEE.ORG
03/22/2005 02:30 PM
Geetha Balasubramanian <[email protected]> wrote (in
<[email protected]>) about 'Radiated
Emission Testing', on Mon, 21 Mar 2005:
> One of our products had been tested by an accredited lab at US
>on May 2004 and found to be compliant with FCC, CE & VCCI. We started
>mass manufacturing the product and it is being sold in the US, Europe &
>Japan markets for the past 6 months. Then came a requirement for that
>product in Taiwan market. Since the May 2004 testing at the US lab was
>not run in a BSMI approved system it became necessary for us to retest
>the same product. This time the product has been tested in an
>accredited lab in Taiwan. The Taiwan lab tests are showing that the
>product is not compliant to the CISPR22 and need a ferrite core in the
>USB cable to make it compliant to the standards. Product tested by the
>US lab & tested by he Taiwan lab are absolutely identical.
> As an engineer responsibled for compliancy I am a bit confused
>now. How to resolve this issue? I request you experts to guide me
EMC testing, even for compliance verification, is not an exact science,
especially when one test shows result just under the limit and another
shows a result just over the limit. The sample tested 10 months ago in
USA is presumably not the same one as tested in Taiwan. But even if it
was, quite a small difference in the layout of the test set-up can make
quite a large difference to the results.
In this case, you are very lucky. You can simply provide a USB cable
with a ferrite, as Taiwan request.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
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