Digital Signal Processing Reference
In-Depth Information
4 mils
215 mV
12 mils
55 mV
4 mils
4 mils
10 mV
Figure 10.8
Top view of 4-mil-wide stripline traces. NEXT falls from 215 mV at minimum spacing to
55 mV when the spacing is increased to three times the trace width. With that same overall spacing,
inserting a guard trace further reduces NEXT to 10 mV.
Crosstalk appearing at the end of the trace closest to the aggressor transmit-
ter is called near-end crosstalk (NEXT).
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Crosstalk appearing at the receiving end of the victim trace is called far-end
crosstalk (FEXT).
•
Microstrip can experience both NEXT and FEXT.
•
Stripline can experience NEXT, but FEXT will be 0 if the line has low loss.
•
The NEXT pulse has the same polarity as the aggressor pulse, and it grows
with the amplitude of the aggressor. The value saturates at a maximum value
when the line is long.
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