FreeLists / si-list / [SI-LIST] Re: EMC Analysis

[steve weir <weirsi@xxxxxxxxxx>]

Hassan,  I treated the problem as two source antennae with matching 
orientation and polarization, and phase WRT the receiving 
antenna.  You raise an interesting point..  However, my intuition 
says that as soon as I insert a receiving antenna with a load that 
Lenz brings us back to the sum of power.  But this is something I 
would have to spend some time on.

Best Regards,


Steve.
At 10:02 AM 3/13/2006, Hassan O. Ali wrote:
>Steve,
>
>I think you assumed that Darshan's numbers are for E-field in dBuV/m 
>(usually used for
>EMI purposes) rather than radiated power.
>
>If the two measured E-field magnitudes are of the same polarity 
>(spacial vector
>direction e.g. both directed in the vertical, up direction) and same 
>temporal (time)
>phase (e.g. 30 degrees), at the far-field measurement point, then 
>indeed the total
>radiated E-field level at that point is the linear sum of the two 
>E-field values.
>
>However, the total radiated power will not be a linear sum of the 
>two radiated power
>levels, since radiated power is proportional to the square of the 
>E-field magnitude.
>
>(|E1|^2 + |E2|^2) not necessarily equal to |E1 + E2|^2
>
>Best regards.
>
>Hassan.
>
>
>
>
>On Mar 13, steve weir <weirsi@xxxxxxxxxx> wrote:
> >
> > Typo, 106.2 not 105.2
> > At 07:03 AM 3/13/2006, steve weir wrote:
> > >Darshan, sum the power in linear form, and convert back to 
> dB.  I get 105.2dB.
> > >
> > >Steve
> > >At 06:55 AM 3/13/2006, Darshan Mehta wrote:
> > >>   Hello Everybody,
> > >>
> > >>  I have one very basic question about EMC Analysis. If we have 2
> > >> nets in design, CLK1 and CLK2, both switching at 200 MHz. If we
> > >> see Electro-Magnetic radiation of 100 dB from CLK1 and 105 dB
> > >> radiation from CLK2, what will be the EMI radiation level at
> > >> System level? Thanks in Advance!
> > >>
> > >>  Best Regards,
> > >>  Darshan Mehta
> > >>
> > >>
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