Harris Atlas DVL400, Technical Manual

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4-30 888-2473-001 2/25/03
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation ATLAS Series™
Remember that the default gain setting for the reject load detectors is Low. This
means that if all of the modules have the correct insertion phase, the reject load will
show minimum reject power on the PA Reject Service screen, and the ADC reading
will be very close to zero. However, at Low gain, this relates to a very coarse setting
where the phasing could be off quite a bit but very little reject power shows up on
the screen due to the lack of sensitivity of the detector.
To compensate for this each detector has two gain settings on the Phase Align
screen, Low and High. Once the reject power is minimised in the Low gain setting,
the gain of the detector can be increased to High to allow for better resolution and
thus better phase alignment of the PA Modules.
4.4.6.3 Precision RF Power Detectors
The precision RF power detectors use the Analog Devices AD8361 TruPower© RF
detector IC. These detectors are configured with a fixed pi-network attenuator on
the input to adjust the input signal to the appropriate level for sensing based on the
source level.
4.4.6.4 Normal Mode / Life Support Mode
The RF Monitor operates in one of two modes, Normal and Life Support (micro
module failure). Normal Mode differs from Life Support mode only in that
reporting capability back to the Main Controller is lost in Life Support mode. All
other fault handling functions, including three strike and comparator thresholds, are
maintained by the CPLD even though the micro module is not functioning.