4-26
888-2463-001
3/6/08
WARNING: Disconnect primary power prior to servicing.
Diamond Series™
Section 4 Theory of Operation
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Over Drive
•
AGC unlocked
•
VSWR fault
4.8.1.3
“No Load” Fault Protection
In case a PA module is not properly positioned in the slot or a circulator does not work,
the Module Controller will turn the PA OFF and indicate a VSWR failure.
4.8.1.4
DC Switch
The DC voltage supplied to the PA Pallets is controlled by the DC switch circuit. When
the module is turned off by the controller or when the module is being removed (hot-
pluggable), the DC voltage is removed from the pallets.
The switch is initially open, and requires an enable command from the Controller
circuit to turn it on. The DC switch can be disabled by pulling the front panel switch
while removing the module or through the Module Controller by sending a disable
command from the Transmitter Control Panel.
The DC Switch circuit has seven current sensors to provide Pallet current information
to the Module Controller circuit.
4.8.2
Phase and Gain
Each PA module has a Phase and Gain board to compensate for small phase and
amplitude differences between modules. This allows the module outputs in the PA
cabinet to maintain the proper phase and amplitude relationships when passed to the
module combiner and minimizes loss.
The function of this assembly is to; provide amplification of the RF signal from the
exciter, provide for adjustable gain to support the PA Modules gain control function,
provide for adjustable phase shift to support the RF Cabinet’s phase control function,
provide a DC signal proportional to RF power applied to the PA Module to support gain
control and diagnostic reporting.
