Ericsson MINI-LINK TN R3 ETSI, Technical Description

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MINI-LINK TN R3 ETSI
4.3.4.11 Branching Filter
On the transmitting side, the signal is fed to the antenna through an output
branching filter. The signal from the antenna is fed to the receiving side through
an input branching filter. The antenna and both branching filters are connected
with an impedance T-junction.
4.3.4.12 Low Noise Amplifier
The received signal is fed from the input branching filter into a Low Noise
Amplifier.
4.3.4.13 Receive RF Oscillator
The frequency of the receiver is controlled in a PLL, including a VCO. An
unlocked VCO loop generates a receiver frequency alarm.
4.3.4.14 Down-converter 1
The first down-converter gives an IF signal of approximately 1 GHz.
4.3.4.15 Receive IF Oscillator
This oscillator is used for the second downconversion to 140 MHz and consists
of a PLL, including a VCO. The VCO is also used for adjustment of the received
140 MHz signal (through a control signal setting the division number in the
IF PLL). A frequency error signal from the MMU is used to shift the receiver
oscillator in order to facilitate an Automatic Frequency Control (AFC) loop.
4.3.4.16 Down-converter 2
The signal is down-converted a second time to the IF of 140 MHz.
4.3.4.17 Received Signal Strength Indicator (RSSI)
A portion of the 140 MHz signal is fed to a calibrated detector in the RSSI to
provide an accurate receiver input level measurement. The measured level is
accessible either as an analog voltage at the alignment port or in dBm from the
management software.
The RSSI signal is also used for adjustment of the output power by means of
the Automatic Transmit Power Control (ATPC).
4.3.4.18 Control and Supervision Processor
The Control and Supervision Processor has the following main functions:
• Collected alarms and status signals from the RAU are sent to the indoor
MMU processor. Summary status signals are visualized by LEDs on the
RAU.
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