Agilent Technologies AuroraPresto, Руководство пользователя

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Aurora Presto
—User Guide
4-26 481801
Gain
The receiver gain sets the amplification of the received
reflections. Increasing the receiver gain can make smaller
reflections easier to display. However, adjusting the receiver
gain higher than is necessary can make smaller faults harder
to detect.
Aurora Presto
’s TDR option selects an appropriate
receiver gain using measurement ranges based on the length
of cable. Each measurement range uses a receiver gain and
pulse width setting typical for fault finding on cables
lengths in the selected range. If you find that the gain and
pulse width is not suitable, you can adjust the receiver gain
and pulse width settings to maximise the performance of
the TDR.
Pulse Widths
Aurora Presto
enables you to select the pulse width settings.
The longer the pulse width, the more energy is produced
and therefore, the signal will travel further down the cable.
Use a short pulse width first, even when testing a long
length of cable. If the fault is not located, select the next
longest pulse width and retest. Keep selecting the next
longest pulse width until the fault is located.
Sometimes longer pulse widths are helpful even for locating
faults that are relatively close. If the fault is very small, the
signal strength of a short pulse width may not be enough to
travel down the cable, locate the fault, and travel back. A
longer pulse width transmits more energy down the cable,
making it easier to detect a small fault.
Setting Up the TDR Tester
DMM (Digital Multimeter) and TDR (Time Domain
Reflectometer) tests are used to test the Electrical Layer of
the local loop.
You can also use the TDR test to find and test the faults
found by the DMM test.
-1-
From the
Select Test Mode
screen select
Manual
Tests
and choose
Physical Layer from the Select
Operation
screen.
481801-7.book Page 26 Thursday, May 23, 2002 10:46 AM