User Manual
Bay Level Offset Calibration
Jan 2002
3-83
SC4812ET BTS Optimization/ATP — CDMA LMF
Introduction
Calibration compensates for normal equipment variations within the
BTS and assures maximum measurement accuracy.
RF Path Bay Level Offset
Calibration
Calibration identifies the accumulated gain in every transmit path (BBX
slot) at the BTS site and stores that value in the CAL file. The BLOs are
subsequently downloaded to each BBX.
Each receive path starts at a BTS RX antenna port and terminates at a
backplane BBX slot. Each transmit path starts at a BBX backplane slot,
travels through the LPA, and terminates at a BTS TX antenna port.
Calibration identifies the accumulated gain in every transmit path (BBX
slot) at the BTS site and stores that value in the CAL file. Each transmit
path starts at a C–CCP shelf backplane BBX slot, travels through the
LPA, and ends at a BTS TX antenna port. When the TX path calibration
is performed, the RX path BLO will automatically be set to the default
value.
When to Calibrate BLOs
Calibration of BLOs is required after initial BTS installation.
The BLO data of an operational BTS site must be re-calibrated once
each year. Motorola recommends re-calibrating the BLO data for all
associated RF paths after replacing any of the following components or
associated interconnecting RF cabling:
BBX board
C–CCP shelf
CIO card
CIO to LPA backplane RF cable
LPA backplane
LPA
TX filter / TX filter combiner
TX thru-port cable to the top of frame
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