User's Manual

RFDS Set–up and Calibration – continued
FEB 2005 1X SC 4812T Lite BTS Optimization/ATP 3-137
PRELIMINARY
RFDS Calibration
The RFDS Calibration option is used to calibrate the RFDS TX and RX
Paths.
TX Path Calibration
For a TX Antenna Path Calibration, the BTS XCVR is keyed at a
pre–determined Power Level and the BTS Power Output Level is
measured by the RFDS. The Power Level is then measured at the TX
Antenna Directional Coupler by the power measuring Test Equipment
Item being used (Power Meter or Analyzer).
The difference (Offset) between the Power Level at the RFDS and
the Power Level at the TX Antenna Directional Coupler is used as
the TX RFDS Calibration Offset Value.
RX Path Calibration
For an RX Antenna Path Calibration, the RFDS is keyed at a
pre–determined Power Level and the Power Input Level is measured by
the BTS BBX. A CDMA signal at the same Power Level measured by
the BTS BBX is then injected at the RX antenna Directional Coupler by
the Communications System Analyzer.
The difference (Offset) between the RFDS–keyed Power Level and
the Power Level measured at the BTS BBX is the RFDS RX
Calibration Offset Value.
RFDS Calibration and the CAL File
The TX and RX RFDS Calibration Offset Values are written to the CAL
File in the Slot[385] Block.
TSIC Channel Frequency
For each RFDS TSIC, the Channel Frequency is determined at the
lower third and upper third of the appropriate band using the frequencies
listed in Table 3-50..
Table 3-50: RFDS TSIC Calibration Channel Frequencies
System Channel Calibration Points
800 MHz (A and B) 341 and 682
1.9 GHz 408 and 791
Before installing any Test Equipment directly to any TX
OUT Connector, verify that there are no CDMA
Channels keyed.
Failure to do so can result in serious personal injury
and/or equipment damage.
WARNING
3