Ap-Rfu - JRC NTG337-EL0 Instruction Manual

3. AP

3.1. AP-RFU

3.1.1. Overview
The AP-RFU consists of three blocks: Antenna section, RF section and IF section.
3.1.2. Antenna section
The omni-directional antenna (with horizontal directivity of 360°) and the Sectoral-Horn-type antenna
( 90° × 10° directivity) look the same.
3.1.3. RF section
In the RF section, the transmission IF signals are up-converted into 24-26 GHz-band RF signals using
the local signal, which is generated by multiplying the 2.4 GHz synthesized oscillator. The next-stage
BPF eliminates unwanted sideband components. The up-converted 24-26 GHz-band RF signals are
amplified up to the desired level then fed to the antenna via the TDD-Switch and the Waveguide Filter.
The received 24-26 GHz-band RF signals by the antenna are fed in to the LNA via the Waveguide Filter
and the TDD-Switch. The output signals of the LNA are down-converted into IF signals using the local
signal, which is generated by multiplying the 2.4 GHz synthesized oscillator. The BPF is employed to
eliminate the image components (interference).
The TDD Switch selects the transmitting or receiving function. Detection of the transmiting burst at the
IF section turns the switch to the transmiting side.
3.1.4. IF section
In the receiving IF section, the output level to the AP-IFU is adjusted by the automatic gain control (AGC)
function, so that the input level of the AP-IFU does not saturate for the reception of the WT signal which
gives highest receiving level. The SAW filter eliminates the adjacent channel interference.
In the transmitting IF section, the detection of the transmiting burst signal controls the TDD-Switch in the
RF section to turn it to the transmiting side. The SAW filter provides the signal delay for the period of the
burst detection and the TDD-Switch turning time, as well as the elimination of the non-desired signal
component.
The IF section also has the compensation functionality for cable losses between the AP-RFU and
AP-IFU.
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