User's Manual

Bay Level Offset Calibration – continued
FEB 2005 1X SC 4812T Lite BTS Optimization/ATP 3-119
PRELIMINARY
Example:
Measured Power Input (at TX Port) = 39.0 dBm
Known BBX TX Power Output = –6.0 dBm
BLO = (39.0) – (–6.0) = 45.0 dB Gain
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 that opens when TX Calibration... or All
Cal/Audit... is selected contains several “user–selectable” Features
that 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 2 is only available if no 1X Cards are selected.
– 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.
Verify BLO Check Box
In both the TX Calibration and All Cal/Audit Dialog Boxes, a Verify
BLO Check Box is provided and checked by default. After the actual
TX Calibration is completed during either the TX Calibration or All
Cal/Audit Process, 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 Check Box 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 Check Box
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, 45.0 +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 BBX Cards.
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