Ap-Rfu; Overview - JRC JUL-6226 User 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.
• Antenna section
The omni-directional antenna (with horizontal directivity of 360°) and the horn-type antenna ( 90° × 10°
directivity) give same shapes of AP-RFU.
• 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.
• 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 control 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 functionarity for cable losses between the AP-RFU and AP-IFU.
The CPU in the IF section performs the AGC, the cable loss compensation , and the monitoring and control
functionalities.
Figure 3-1 is a block diagram of the AP-RFU.