Vf/ac balance, Active – EXFO MaxTester 635 User Manual
Page 182
Frequency Tests
174
MAX-635
VF/AC Balance
VF/AC Balance
The VF/AC Balance test allows you to check that the VF longitudinal
balance ratio for the twisted pair complies with applicable standards so as
to reduce the effects of common-mode voltage to ground. The test is a
measurement of how much the T/A leg is like the R/B leg in electrical
characteristics, measured by how much noise the line can mitigate (in dB).
It is an overall health indicator and a quick way to tell if the line is in good
condition. The better the longitudinal balance of the cable pair, the higher
the dB reading.
The name of the frequency test depends on the selected Standard:
ANSI: VF Balance
ITU: AC Balance
Active
The Active function takes a balance measurement,
displaying and updating results in real time, until you
stop the test. The last valid results then remain
displayed.
Current Group is the current test group name, for
example Frequency Tests.
Current Test displays the test being measured.
Here you can switch to another test from the given
list. However, this action will terminate the
ongoing measurement test.
Threshold Settings button opens a new page that
allows you to set the VF/AC Balance threshold.
Result displays the pass/fail status and Active VF/AC Balance value.
Test Status displays the current state of measurement or an error
message.