Chapter 5
Cable Test Descriptions
Page 5-9
Power Sum NEXT
NEXT (Near End Crosstalk) is a measure of noise coupled from
one pair to another pair within a four pair cable.
Power Sum NEXT is a sum of the pair-to-pair NEXT coupled from
all adjacent pairs.
Signal generators
Signal measurement
1
2
3
6
4
5
M
7
8
Crosstalk
Figure 5-1. Power Sum NEXT Measurement
As shown above, Power Sum NEXT is a sum of the pair-to-pair
NEXT and is always greater than any pair-to-pair NEXT.
The Power Sum NEXT test uses the same test limit as pair-to-pair
NEXT. Since Power Sum NEXT is always greater than pair-to-pair
NEXT, the Power Sum NEXT test holds the cable up to a higher
standard.
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