User Manual
Adjusting for loss68P09255A57-2
Aug 2002
SC4812ET Optimization/ATP Manual Software Release R16.1.x.x
PRELIMINARY
3-79
At sites WITHOUT RFDS option, BLO is approximately
42.0 dB ±4.0 dB. A typical example would be TX output power
measured at BTS (36.0 dBm) minus the BBX TX output level
(approximately -6.0 dBm) would equate to 42 dB BLO.
The TX Bay Level Offset at sites WITH the directional coupler option,
is approximately 41.4 dB ±3.0 dB. TX BLO = Frame Power Output
minus BBX output level.
Example: TX output power measured at RFDS TX coupler
(39.4 dBm) minus the BBX TX output level (approximately
-2.0 dBm) and RFDS directional coupler/cable (approximately
-0.6 dBm) would equate to 41.4 dB BLO.
The LMF Tests menu list items, TX Calibration and All Cal/Audit,
perform the TX BLO Calibration test for a XCVR(s). The All Cal/Audit
menu item performs TX calibration, downloads BLO, and performs TX
audit if the TX calibration passes. All measurements are made through
the appropriate TX output connector using the calibrated TX cable setup.
Test Pattern Drop-down Pick List
Pilot is shown as the default setting in this pick list box. The full range
of available selections and their descriptions are as follows:
Standard
- performs calibration or audit using pilot, paging, synch, and
six traffic channels with IS-97-specified gain. This pattern setting
should be used for all non-in-service calibrations and audits. Using this
pattern setting requires the selection of both a BBX and at least one
MCC.
Pilot
(default) - performs calibration using only the pilot channel. This
pattern setting should be used for in-service calibrations, and requires
selection of only a BBX.
CDFPilot
-This pattern setting is for advanced users. It performs
calibration or audit using the CDF value for pilot gain and IS-97 gain
values for all the other channels included in the Standard pattern setting
(paging, synch, and six traffic). Using this pattern setting requires the
selection of both a BBX and at least one MCC.
CDF
- This pattern setting is for advanced users who need to use CDF
gain settings for all channels included in the Standard pattern setting
(pilot, paging, synch, and six traffic). Using this pattern setting requires
the selection of both a BBX and at least one MCC.
Verify BLO
In both the TX Calibration and All Cal/Audit dialog boxes, a Verify
BLO checkbox 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 checkbox should be unchecked or the additional path losses
should be added into each applicable sector using the
Util>Edit>TX Coupler Loss function.
3