EXFO MaxTester 635 - Manual (Page 156)

Noise Tests
148 MAX-635
VF Impulse Noise
VF Impulse Noise
The VF Impulse Noise test allows you to measure voice frequency impulse
noise on the circuit under test.
Count
The Count function displays and updates results in real time, for the length
of time set in Test Duration or less if you stop the test. The last valid results
then remain displayed.

Current Group is the current test group name, for
example Noise 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.

VF Noise Filter allows you to define the voice
frequency noise filter to be used, dependent on
ITU or ANSI Standard mode and Noise Filter set
in Setup/Application Settings.

Termination Resistance is a read-only value of
600
Ω .

Test Duration allows you to set the length of time to run the test from a
list of values.

Threshold Settings button opens a new page that allows you to set the
VF impulse noise thresholds.

Result displays the High, Mid, Low counts, respective detection levels,
and Elapsed Time. The pass/fail status of the Mid level is displayed
after 1 s and then periodically refreshed, until you stop the test.

Test Status displays the current state of measurement or an error
message.