UltraCAD Design, Inc


EMI (Electromagnetic Interference) Articles


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Loop Areas, Close 'Em Tight!  
  Current MUST flow in a closed loop. It is important for designers to know where the signal RETURN current is flowing, because EMI can be directly related to the area defined by the signal trace and its return path. This is explained in this article that ran in the January, 1999, issue of the magazine.
Slots in Planes: Don't Use 'Em!  
  This article covers three important reasons why slots in planes should be avoided: (1) they can increase EMI, (2) cause a loss of control over impedance, and (3) increase crosstalk. See the details in this article that ran in the March, 1999, issue of the magazine.
Where's the Loop?  
  It seems like a contradiction to say that current is a constant everywhere within a closed loop and yet it takes a finite amount of time for current to propagate down a transmission line. Find out how to resolve these seemingly contradictory statements in this article that appeared in the March, 2001, issue of the magazine.
Crosstalk, EMI, and Differential Z  
  Appearing in the June, 2001, issue, this article points out the the fundamental nature  of crosstalk, EMI, differential signal coupling and television transmission are all the same and caused by the same phenomenon.

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