User's Manual

Chapter 12 Board Installation
12-3
Filter the weak signals received by an antenna and amplify them with low noise.
Distribute power for the signals amplified with low noise, output them to the RSM and
the TEST_PORT through two splitters.
Provide duplex functions.
Filter forward transmitting power signals.
Monitor the low noise amplifier state.
Check the standing wave of the transmission channel to determine the matching state
of the antenna feeder.
Monitor the forward power, including the total power and the single carrier power.
Provide more accurate channel power detection table through frequency selective
circuit, thus a more accurate output power detection value for each carrier.
Incorporate in the automatic calibration of the output power.
Inject and acquire the BTM signals (DUP forward acquisition and DUP reverse/DIV
injection).
Provide the TX test port for pre-distortion sampling.
Report to the RMM via the serial port about the power, VSWR alarms, and the LNA
state. The RMM also controls the variable attenuator on the power detection link of the
PVD for the expansion of the dynamic range of the detection link.
Support external tower top amplifier with the LNA design for links that makes gain
adjustment through the background.
Detect the power of the all-channel bandwidth (5M) of 4-carrier and a given carrier at
the same time.
12.2.2 Power Amplifier (PA)
The PA is the power amplification module for the whole RFS. With its great working
current and high working temperature, it is required to provide some special linearity to
be applied to CDMA systems. Therefore, the implementation of it, a key module in the
BTSB, is a great challenge. High PA (for signal carrier amplification) or linear PA (for
multi-carrier amplification) can be chosen for the base station. This section only
addresses the principles of the linear PA (LPA).
The functions and principles of the LPA are as follows: