User Manual

Bay Level Offset Calibration – continued
PRELIMINARY
SC 4812ETL BTS Optimization/ATP
08/15/2000
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file. TxCal data is sent first, C[1] – C[60]. BBX2 slot 1’s 10
calibration points are sent (C[1] – C[20]), followed by BBX2 slot 2’s
10 calibration points (C[21] – C[40]), etc. The RxCal data is sent next,
followed by the RxDCal data.
S Temperature compensation data is also stored in the cal file for each
slot.
Test Equipment Setup:
RF Path Calibration
Follow the steps outlined in Table 3-32 to set up test equipment.
Table 3-32: Test Equipment Setup (RF Path Calibration)
Step Action
NOTE
Verify the GPIB is properly connected and turned on.
! CAUTION
To prevent damage to the test equipment, all transmit (TX) test connections must be via the 30 dB
directional coupler for 800 MHz or via a 30 dB coupler with a 20 dB in–line attenuator for 1900 MHz.
1 Connect the LMF computer terminal to the BTS LAN A connector on the BTS (if you have not
already done so). Refer to the procedure in NO TAG.
S If required, calibrate the test equipment per the procedure in Table 3-24.
S Connect the test equipment as shown in Figure 3-14 and Figure 3-15.
Transmit (TX) Path Calibration
The assigned channel frequency and power level (as measured at the top
of the frame) for transmit calibration is derived from the site CDF file.
For each BBX2, the channel frequency is specified in the
ChannelList
CDF file parameter and the power is specified in the SIFPilotPwr
CDF file parameter for the sector associated with the BBX2 (located
under the
ParentSECTOR field of the ParentCARRIER CDF file
parameter).
The calibration procedure attempts to adjust the power to within +
0.5 dB
of the desired power. The calibration will pass if the error is less than
+
1.5 dB.
The TX Bay Level Offset at sites WITHOUT the directional coupler
option, is approximately 42.0 dB ±3.0 dB.
S 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 BBX2 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 BBX2 output level.
S Example: TX output power measured at RFDS TX coupler
(39.4 dBm) minus the BBX TX output level (approximately
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