Amphenol Procom PRO-DAR4 Podręcznik użytkownika - Strona 8
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Drukuj stronę6 Circuit description
6.1
Amplifier/splitter modules
The PRO-DAR multicouplers contains a dedicated RF amplifier system, followed by
a passive n-way power splitter circuitry corresponding to the particular number of outputs.
The RF amplifier system compensates for the n-way splitter loss + circuitry insertion loss.
The RF amplifier system is of the redundant type. It is designed as 2 separate identical
amplifier stages, which operates in parallel.
On the amplifier input the RF signal is divided in 2 identical portions in a 2-way power
splitter, and the signal from each splitter output is fed to the input of the 2 amplifier stages.
On the amplifier output, the output signal from each amplifier stage is combined in a
2-way power combiner.
This redundant RF amplifier design provides maximum operational reliability for the
multicoupler. If one of the amplifier stages fails, the amplifier will continue to operate with
gain around -6 dB relative to the normal gain, providing uninterrupted service with only
minor performance deterioration.
The RF amplifier has low noise figure to ensure lowest possible signal-to-noise ratio
deterioration of the distributed RX signal.
Simultaneously, the RF amplifier has very good large signal capabilities, in order to avoid
intermodulation between strong signals in the distributed RF signal spectrum.
Moreover, paralleling of two amplifier stages provides further increased amplifier dynamic
range compared to a similar single stage amplifier design.
The output signal from the amplifier system is fed to an n-way passive power splitter
circuitry, where n corresponds to the number of outputs of the particular multicoupler.
The PRO-DAR4 is provided with a 4-splitter circuitry at the output. The 4 outputs from the
splitter form the 4 identical RX outputs.
The PRO-DAR8 is provided with a 2-splitter, followed by 2 identical 4-splitters, which forms
the 8 identical RX outputs.
The PRO-DAR12 and PRO-DAR16 are provided with a 4-splitter, followed by 3 or 4
identical 4-splitters, which forms the 12 or 16 identical RX outputs.
The power splitter circuitry is of the Wilkinson type and provides high isolation between the
individual RX outputs, ensuring insignificant low mutual coupling between the connected
receivers.
Gain of the amplifier is adjusted individually to compensate for the particular loss in the
different splitter systems.
See chapter 5: Block diagrams.
In order to maintain a high input dynamic range of the connected receivers (ability to
withstand strong antenna signals), RF gain from ANT input to RX output is selected to be
low, nominally +2 dB.
This gain value is factory adjusted and gain adjustment is not user accessible.
RF amplifier and power splitter circuitry are of wideband structure, meaning that signals in
the whole frequency range from 30 MHz to 960 MHz will be amplified equally.
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