Andrew Wireless Innovations Group MRB-LMR User Manual

The controller monitors the status of the following system components:

•

 PA power output

•

 PA temperature

•

 PA shutdown

•

 power supply temperature

•

 average 26 VDC and 12 VDC output voltages

•

 AC mains presence

•

 DC output VSWR (when installed)

The controller also routes the DC power to the VSWR module.

For general use, two alarm outputs are provided that can be user-configured
during installation.  The outputs are normally open relay contact pairs, which
are closed when no alarm condition is present.  These signals are provided on
four of the seven pins of a terminal block on the controller board.

The PA combiner/splitter module (see Figure 2-4) splits the input signal,
distributes it to the PAs and combines it after amplification.  Identical hybrid
design is used to ensure maximum amplitude and phase matching of the
downlink signal.

The LNA (see Figure 2-4) maintains dynamic range for uplink mobile
signals.  The LNA provides low noise figure and high input IP3 so the booster
does not decrease sensitivity or increase distortion in the system.

The gain of the LNA chain after duplexer and cable losses is nominally 20 dB
with the uplink attenuation set to 0 dB. Using the internal software, the gain
can be reduced by increasing the attenuation in 1 dB steps up to 15 for
optimal IP3, or where equal uplink and downlink booster gain is not
necessary.  The same LNA is used in the diversity option and the attenuation
setting is ganged so each uplink path is set for equal gain.