Anrtisu Cell Master MT8212B, Руководство пользователя, Страница: 158 / 294

Distance-To-Fault (DTF) Transmission Line Test
The Distance-To-Fault transmission line test verifies the performance of the transmission
line assembly and its components and identifies the fault locations in the transmission line
system. This test determines the return loss value of each connector pair, cable component
and cable to identify the problem location. This test can be performed in the DTF–Return
Loss or DTF–SWR mode. Typically, for field applications, the DTF–Return Loss mode is
used. To perform this test, disconnect the antenna and connect the load at the end of the
transmission line.
Required Equipment
q
Cell Master Model MT8212B
q
Precision Open/Short, Anritsu 22N50 or
Precision Open/Short/Load, Anritsu OSLN50LF or
Anritsu InstaCal Module, ICN50
q
Precision Load, Anritsu SM/PL
q
Test Port Extension Cable, Anritsu 15NNF50-1.5C
q
Optional 510-90 Adapter, DC to 7.5 GHz, 50 ohm, 7/16(F)-N(M)
Device Under Test
q
Transmission Feed Line with Load
Procedure - Return Loss Mode
The following steps explain how to make a DTF measurement in return loss mode.
Step 1.
Press the MODE key.
Step 2. Select
DTF-Return Loss
using the Up/Down arrow key and press ENTER .
Step 3. Connect the Test Port Extension cable to the RF port and calibrate the Cell Mas-
ter as described on page 3-2.
Step 4. Save the calibration set up (page 3-14).
Step 5. Connect the Device Under Test to the Cell Master phase stable Test Port Exten-
sion cable. A trace will be displayed on the screen as long as the Cell Master is
in sweep mode.
Step 6. Press the FREQ/DIST key.
Step 7. Set the
D1
and
D2
values. The Cell Master default for D1 is zero.
Step 8. Press the
DTF Aid
soft key and select the appropriate
Cable Type
to set the
correct propagation velocity and attenuation factor.
NOTES: Use the provided Handheld Software Tools program cable editor to
add new cable information to the Cell Master cable list. Refer to the Handheld
Software Tools chapter for more information.
Selecting the right propagation velocity, attenuation factor and distance is very
important for accurate measurements, otherwise the faults can not be identified
accurately.
Step 9. Press SAVE DISPLAY (page 3-15) name the trace, and press ENTER .
4-6
Chapter 4 Cable & Antenna Measurements