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Performing Tests
Return Loss Measurement
Chapter 4
O:\Manuals\E6385A_Cdma\Book\perf-tst.fm
82
Return Loss Measurement
This measurement is used to determine the return loss of a cable, antenna, or other
device in the swept mode. An SWR bridge and a 6-dB pad are connected to the Test Set.
The Test Software uses the pad to improve the mismatch between the SWR bridge and
the ANT IN port on the Test Set. A reference level is measured with an open or short on
the bridge and then the return loss is measured with the cable or antenna-under-test.
Measured values for minimum and maximum return loss are displayed.
This measurement requires two external 6-dB attenuators (pads), two type-N cables,
and an SWR bridge. These parts are not standard equipment with the Test Set, but are
included in the optional Agilent Technologies E6554A 8935 RF Tools Hardware
Accessory Kit (see “Accessory Kits” on page 17).
This test sends no control commands to the MSC.
Parameters and Specifications Used
The following specifications and parameters are used when running this test. See
Chapter 5, “Reference,” for descriptions of the specifications and parameters.
Parameters:
• None used for this test.
Specifications (Pass/Fail Limits):
• None used for this test.
Select and Run the Test
Perform the Return Loss Measurement as follows:
Step 1. From the Lucent CDMA Tests Main Menu screen, select the Calibration/Utilities
field. The Test Software will display the Calibration/Utilities Menu screen.
Step 2. Select the Return Loss Test field.
Step 3. If prompted to do so, remove the RF connections from the Test Set and press the
k1
(Proceed) key to perform a channel power calibration. If channel power was recently
calibrated, the Test Software might not prompt you to re-calibrate before starting the
Return Loss test.
Step 4. Select the loss Measurement Type field and select the following:
• Swept will measure the loss over the frequency range that you specify in the Start
Frequency and Stop Frequency settings. The Maximum Expected Loss for the
device to be tested will be used to adjust the scale on the results plot. Use a value
slightly greater than expected for the best display resolution. The Duplex Out Level
into the device being tested may be adjusted if necessary.
• Discrete will measure the loss at the frequency that you specify by entering the
Channel Number to be tested.