User Manual

Loss/Gain Offset
68P09255A57-2
Aug 2002
SC4812ET Optimization/ATP Manual Software Release R16.1.x.x
PRELIMINARY
3-70
Table 3-32: Test Equipment Calibration
Step Action
3 Click on Continue to close the Directions window. A status window is displayed.
4 Click on OK to close the status report window.
Calibrating Cables
The cable calibration function is used to measure 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 procedures.
Measure the loss of a short cable. This is done to compensate for any
measurement error of the analyzer. The short cable, which is used only
for the calibration process, is used in series with both the TX and RX
cable configuration when they are measured. 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. This deduction is done so any error in the
analyzer measurement will be adjusted out of both the TX and RX
measurements.
Measure 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
the test equipment.
Measure the short cable plus the TX cable configuration loss is
measured. 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 BTS type. The total loss of
the path loss of the TX cable configuration must be as required for the
BTS (normally 30 or 50 dB). The Motorola Cybertest analyzer is
different in that the required attenuation/load is built into the test set
so the TX cable configuration consists only of the required length
coax cable.
Calibrating Cables with a CDMA Analyzer
The Cable Calibration menu item from the Util menu list is used to
calibrate both TX and RX test cables for use with CDMA LMF.
NOTE
LMF cable calibration cannot be accomplished with an
HP8921A analyzer for 1.9 MHz. A different analyzer type or the
signal generator and spectrum analyzer method must be used
(refer to Table 3-34 and Table 3-35). Cable calibration values
must be manually entered if the signal generator and spectrum
analyzer method is used. For the HP8921A, refer to Appendix F.
The test equipment must be selected before this procedure can be started.
Follow the procedure in Table 3-33 to calibrate the cables.
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