User Manual

Test Set Calibration – continued
PRELIMINARY 2
SC 4812ET BTS Optimization/ATP – CDMA LMF
July 1999
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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.
 The short cable plus the RX cable configuration loss is measured. 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.
 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, 40, 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.
Cable calibration cannot be accomplished with an HP8921
analyzer. A different analyzer type or the signal generator
and spectrum analyzer method must be used (refer to
Table 3-30 and Figure 3-23). Cable calibration values must
be manually entered if the signal generator and spectrum
analyzer method is used.
NOTE
The test equipment must be selected before this procedure can be started.
Follow the procedure in Table 3-29 to calibrate the cables. Figure 3-15
illustrates the cable calibration test equipment setup.
Table 3-29: Cable Calibration
 Step Action
1 From the Util menu, select Cable Calibration. A Cable Calibration window is displayed.
2 Enter a channel number(s) in the Channels box. Multiple channels numbers must be separated
with a comma, no space (i.e., 200,800). When two or more channels numbers are entered, the
cables will be calibrated for each channel. Interpolation will be accomplished for other channels as
required for TX calibration.
3 Select TX and RX CABLE CAL, TX CABLE CAL or RX CABLE CAL in the Cable
Calibration picklist.
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