User's Manual
Bay Level Offset Calibration
68P09255A69-3
Aug 2002
1X SC4812ET Lite BTS Optimization/ATP Software Release 2.16.1.x
PRELIMINARY
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TX Calibration and the LMF
The LMF Tests > TX > TX Calibration... and Tests > All Cal/Audit...
selections perform TX BLO calibration testing for installed BBX(s). The
All Cal/Audit... selection initiates a series of actions to perform TX
calibration, and if calibration is successful, download BLO and perform
TX audit. The TX Calibration... selection performs only TX
calibration. When TX Calibration... is used, BLO download and TX
audit must be performed as separate activities. The CDMA Test
Parameters window which opens when TX Calibration... or All
Cal/Audit... is selected contains several user-selectable features which
are described in the following subsections.
Rate Set Drop-down Pick List
The Rate Set Drop-down Box is enabled if at least one MCC card is
selected for the test. The available options for TX tests are 1 = 9600, and
3 = 9600 1X. Option 3 is only available if 1X cards are selected for the
test. The available transfer rate options for RX tests are 1 = 9600 and
2 = 14400. Option 2 is only available if no 1X cards are selected.
Verify BLO Checkbox
A Verify BLO checkbox is provided and checked by default. After the
actual TX calibration is completed, the BLO derived from the calibration
is compared to a standard, acceptable BLO tolerance for the BTS. In
some installations, additional items may be installed in the transmit path.
The additional change in gain from these items could cause BLO
verification failure and, therefore, failure of the entire calibration. In
these cases, either the Verify BLO checkbox should be unchecked or the
additional path losses should be added into each applicable sector using
the Util > Edit > TX Coupler Loss... function.
Single-Sided BLO Checkbox
An acceptable range of BLO values for each type of BTS is established
to allow for tolerance variations in all the components of the RF chain.
This acceptable range, 42+
5 dB for example, is very wide to
accommodate the redundant BBX in the BTS. This is a much wider
tolerance than necessary for the primary BBXs. Primary BBXs normally
will have BLOs in the lower half of the range. Using the example range,
this would be from 37 to 42 dB. Checking the Single-Sided BLO
checkbox should only be done when calibrating primary BBXs because
it will reduce the acceptable BLO value variations to the lower half of
the range. Because this is a much more stringent tolerance, calibrations
run with Single-Sided BLO are more likely to fail and should only be
attempted by an experienced CFE. Never select Single-Sided BLO
when calibrating a redundant BBX.
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