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Re: RJ-45 common mode radiated emissions testing




Rick,

The data helps. However, is it possible to redo with proper terminations
on the end of the cable. You need both differential and common mode
terminations. Unterminated end reflections will increase mode
conversion.

Jack Andresen
*************************

Rick Brooks wrote:

>
>
> I have posted the test setup and results of a radiated emissions test
> that I did recently in a 10 meter anechoic chamber.
>
> The test was to try to determine what common mode signal voltage would
> produce a radiated field that would be at the
> compliance limit, class B in this case.
> I hope that this data will help us to specify a noise requirement for
> the DTE power from the PSE, as well as the PD.
>
> It is important to understand that the radiated emissions requirements
> only cover from 30MHz and higher.
> The spectral region from 500 kHz to 30 MHz, is obviously of importance
> to 10/100/1000, but I don't cover it here.
>
> The pdf file is at:
>
> ttp://www.ieee802.org/3/power_study/public/email_attach/RJ45_rad_emissions.pdf
>
> comments, questions?
>
> thanks,
> - Rick