User's Manual

Bay Level Offset Calibration

3-112 1X SC 4812T Lite BTS Optimization/ATP FEB 2005

PRELIMINARY

Introduction

Bay Level Offset (BLO) Calibration is the central activity of the

Optimization Process. BLO Calibration compensates for normal

equipment variations within the BTS RF Paths and assures that the

correct Transmit Power is available at the BTS Antenna Connectors to

meet site performance requirements.

What is BLO Calibration?

Description

BLO Calibration is the complete title of what is normally referred to as

“Calibration.” Calibration identifies the accumulated Gain in every

Transmit Path at the BTS Site.

The Transmit Path BLO Values determined during Calibration are stored

in the LMF Calibration Data File, and are subsequently downloaded to

each BBX. When Transmit Path Calibration is performed, Receive Path

BLO Values are automatically set to the Default Value in the LMF

Calibration File and downloaded.

BTS RF Path Descriptions

Transmit (TX) Path

A TX Path starts at an SCCP Cage BBX Backplane Slot, travels

through the CIO Card, is routed to the Power Amplifier (PA) Trunking

Module for Sector Phase Shifting, through the PAs, back through the PA

Trunking Module for Sector Phase Selection, through the TX Bandpass

Filter (Starter Frames) or 2:1 TX Combiner (Expansion Frames),

through the Transmit and Receive Filter (TRF) or Duplexer TX/RF Filter

(DRF), and ends at the TRF or DRF Antenna Connector..

Receive (RX) Main Path

A Main RX Path starts at ANTENNAS Connectors 1A, 2A, or 3A and

travels through the associated TRF or DRF, the MPC in the SCCP Cage

MPC–1 Slot, the CIO Card, and terminates at a Backplane BBX Slot in

the SCCP Cage..

Diversity RX Path

Diversity RX Paths differ for SC4812T Lite Starter and Expansion

Frames. The following describe each type of path.:

S Starter Frame Diversity RX Path – A Starter Frame Diversity RX

Path is the same as a Main RX Path except that it starts at

ANTENNAS Connectors 1B, 2B, or 3B, travels through the

associated TRF or DRF, and the MPC Card in SCCP Cage MPC–2

Slot.