User's Manual

Table Of Contents
Test Set Calibration
68P09255A61-4
Aug 2002
1X SC 4812T BTS Optimization/ATP Software Release 2.16.1.x
FIELD TRIAL
3-62
Calibrating Cables
The cable calibration function measures the loss (in dB) for the TX and
RX cables that are to be used for testing. A CDMA analyzer is used to
measure the loss of each cable configuration (TX cable configuration and
RX cable configuration). The cable calibration consists of the following:
Measuring the loss of a short cable - This is required to compensate
for any measurement error of the analyzer. The short cable (used only
for the calibration process) is used in series with both the TX and RX
cable configuration when measuring. The measured loss of the short
cable is deducted from the measured loss of the TX and RX cable
configuration to determine the actual loss of the TX and RX cable
configurations. The result is then adjusted out of both the TX and RX
measurements to compensate for the measured loss.
Measuring the short cable plus the RX cable configuration loss -
The RX cable configuration normally consists only of a coax cable
with type-N connectors that is long enough to reach from the BTS RX
port of the test equipment.
Measuring the short cable plus the TX cable configuration loss -
The TX cable configuration normally consists of two coax cables with
type-N connectors and a directional coupler, a load, and an additional
attenuator (if required by the specified BTS). The total loss of the path
loss of the TX cable configuration must be as required for the BTS
(normally 30 or 50 dB).
Calibrating Cables with a CDMA Analyzer
Cable Calibration is used to calibrate both TX and RX test cables.
Follow the procedure in Table 3-28 to calibrate the cables. Figure 3-10
illustrates the cable calibration test equipment setup. Appendix F covers
the procedures for manual cable calibration.
NOTE
LMF cable calibration for PCS systems (1.7/1.9 GHz) cannot be
accomplished using an HP8921 analyzer with PCS interface or
an Advantest analyzer. A different analyzer type or the signal
generator and spectrum analyzer method must be used (refer to
Table 3-29 and Figure 3-20). Cable calibration values are then
manually entered.
Prerequisites
Ensure the following prerequisites have been met before proceeding:
Test equipment to be calibrated has been connected correctly for cable
calibration.
Test equipment has been selected and calibrated.
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