Wireless WaveNet Link AX, Инструкция по установке и эксплуатации

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WaveNet Link AX Installation and Operations Manual
2.5.3 Synthesizer
The FPGA provides four 22-bit streams in a serial format loaded to the synthesizer. This data
provides all of the possible frequencies at which the system can operate. Depending upon the
dip switch settings selected, the actual frequency being used is selected. When the reset
button is pressed, the FPGA will reload this data to the synthesizer.
Frequency Synthesis
The local oscillator frequencies used in the Link AX are all synthesized from a 19.2 MHz,
±
2.5
PPM reference oscillator. The overall frequency stability of the radio is
±
2.5 PPM, directly
reflecting the reference oscillator stability.
A dual frequency synthesizer chip is used to control both the first and second local oscillator
loops. This chip supports one high frequency oscillator, up to 1.5 GHz, and one lower
frequency oscillator to be used as a second LO.
The first local oscillator VCO operates at one half the transmitter output frequency, and
changes with the transmit channel selected. The first LO consists of a bipolar VCO operating
at 2.887 GHz
±
25 MHz. The output of this VCO is buffered and then passed through a X2
prescaler chip before being fed back to the synthesizer chip. The phase comparison frequency
for the first LO is 320 kHz.
After amplification the 2.887 GHz signal is passed through a frequency doubler to create the
5.775 GHz signal that is applied to the mixer stages.
The second local oscillator consists of a VCO that is phase locked to 404.88 MHz. This auxiliary
synthesizer is operating with a phase comparison frequency of 240 kHz.
2.6 Indoor Unit
An optional Indoor Unit (IDU) can be used with the Link AX to provide diagnostics and
troubleshooting aid to maintenance personnel. The IDU contains a single LED that illuminates
with the presence of ATM25 data and power. Additionally a BNC connector is provided so that
maintenance personnel can view RSSI voltage inside the building. The IDU is NOT required
for operation of the Link AX radio system. Figure 2.3 shows the Link AX IDU.
Figure 2-3 Link AX Indoor Unit (IDU)
Radio Unit Connection
Measurement Port
RSSI (BNC Type Connector) System power and
RF Status indicator
(Green LED)
ATM 25 interface
Connection
WL238005