EXFO CableSHARK P3, Руководство пользователя, Страница: 122 / 321

VF / DSL Cable Qualifier
110
EDIT /
SELECT MAIN
MENU
Test Type :
Term Impedance :
Termination:
Noise Filter :
Imp Nse Threshold:
Plot Interval:
Meas Time (Hour):
Measurement Units:
100 OHMS
TERMINATED
NO FILTER
43
dBm
1 Minute
1
E F
CHG
IMPULSE HISTOGRAM
WARNING
Note: telephone cables may have dangerous A.C. or D.C.
voltages on them, therefore caution should be taken when
connecting this test set.
!
SELECT
NEXT
-
F
IGURE
8.4.1D – I
MPULSE
H
ISTOGRAM
T
EST
S
ETUP
M
ENU
The NOISE TEST SETUP Menu has several options that appear at the upper part of the screen (see the
previous illustration). The parameters can be modified to customize a noise test. The noise test setup
options are described as follows:
TEST TYPE:
Select from NOISE PSD Next/Fext 2.2 MHz, NOISE PSD Next/Fext 6.0MHz,
IMPULSE NOISE and IMPULSE HISTOGRAM.
The PSD NOISE test measures the PSD noise energy and displays the result in
terms of dBm/Hz. For this test, no test signal is impressed onto the line under
test. The background cable signal is converted to a RMS voltage reading.
For Impulse Noise, no test signal is impressed onto the line under test. The
background cable signal is analyzed for a predetermined time to count the
number of noise spikes higher than the user selected threshold.
For Impulse Histogram, the CableSHARK plots impulse noise spikes over a user
definable time period.
TERM IMP:
The CableSHARK's impedance needs to match the characteristic impedance of
the cable. This causes the CableSHARK at either end of a test (including Single