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WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
Maxiva ULX COFDM Series
4.6.3.6 Signal Distribution Board
Signal Distribution Board serves to route analog and digital control and monitoring data
between 4 other board subassemblies, such as:
• Monitor Board
• Four PA Pallets
• I/O Connector Board
• 4-way splitter board
4.6.3.7 PA Module Phase Alignment
PA modules do not require phase alignment to optimize combining of modules. The
modules are phase optimized at the factory to produce 90 degrees of phase shift (input
to output at 800 MHz) with a tolerance of 5%. The factory phase alignment of each
module insures that modules can be used in any position in the transmitter with minimal
effects on transmitter operation.
4.6.3.8 PA Module Splitter
The power splitter 9010222071G is used in the Maxiva PA Module (p/n 9710040004)
to equally divide RF signal that is applied on the input of the splitter between 4 power
amplifier pallets. The splitter has a broad band response that covers the entire TV Band
IV/V frequency range, and requires no tuning. Insertion phase of the signals at each of
the outputs is configured to provide minimum loss re-combining by the power
combiner. The splitter contains two splitting stages. Each stage equally distributes the
input signal between two outputs. Each RF output is isolated from the others to improve
amplitude balance between amplifier pallets. The splitter contains envelope detector
circuitry that delivers a sample of the down converted signal to the Monitor Board (p/n
901 0222 051G). It contains a directional coupler and a logarithmic amplitude detector.
4.6.3.9 PA Module Pallet Combiner
The power combiner (p/n 901 0222 091G) is used as part of the Maxiva PA Module (p/
n 971 0040 004) to combine the RF signals from the outputs of the 4 power amplifier
pallets, and deliver the resulting signal to the output port. The combiner has a
broadband response that covers the entire TV Band IV/V, and requires no tuning. The
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