IDEAL Networks LanTEK III, Руководство пользователя

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LanTEK III 161809 Iss 2
User Manual Page63
combinations (1-2 to 3-6, 3-6 to 1-2, 1-2 etc.). This results in a total of 12
measurements.
6.10 Power Sum NEXT, Power Sum ACR-F (ELFEXT)
Power Sum-Tests determine the crosstalk effects of three transmitting wire pairs on the
fourth wire pair in the same cable.
1
2
3
6
4
5
7
8
2
1
6
3
5
4
8
7
Fig. 77 Effects of 3 Pairs on 1 Pair
When using Power Sum NEXT, four (4) calculations on each cable end and on each wire
pair combination (pairs 1-2, 3-6 and 4-5 to 7-8 etc.) are performed. A total of eight (8)
values is obtained.
Fig. 78 Power Sum NEXT
NOTE:
The Power Sum NEXT values are usually 2 - 3 dB below the value (= stronger crosstalk)
than with conventional NEXT measurement.
When using Power Sum ACR-F (Power Sum ELFEXT), four (4) calculations on the side of
the Display handset (DH) and on each wire pair combination (pairs 1-2, 3-6 and 4-5 to 7-8
etc.) are performed. A total of eight (8) values is obtained.