4-4 888-2586-001 9/15/06
WARNING: Disconnect primary power prior to servicing.
Platinum Z16HD+
Section 4 Overall System Theory
outputs from the IPA_AB Backplane board drive the inputs to Z-Planes A and B. The 2
outputs from the IPA_CD Backplane Board drive the inputs to Z-Planes C and D.
4.2.2.2 PA
The Z16HD+ PA can be broken down into several levels. First, there are two Power
Blocks, each Power Block contains two Z-Planes, each of which could be considered
Power Blocks. The other 3 Z-Planes are identical. Next, each Z-Plane can also be
broken down into 2 parts, a Divider Board and a Combiner Board.
4.2.2.3 Z-Plane Divider Board
The Divider Board takes the IPA input and uses a 2 way Wilkinson splitter to drive two
more 4 way Wilkinson splitters. This provides the necessary 8 drive signals for the 8
PAs (not modules) connected to Z-Plane A. The PAs are labeled A1-A8 for Z-Plane A,
B1-B8 on Z-Plane B, C1-C8 on Z-Plane C and D1-D8 on Z-Plane D. PAs 1-4 on each
Z-Plane are located in the front of the transmitter, while 5-8 are located in the rear of the
transmitter. Any four PAs on the same Z-Plane labeled 1-4 are considered a
FOURSOME, because they are connected to the same 4 Way combiner. Any PAs
labeled 5-8 are also considered a Foursome. Here is a list of the 8 Foursomes in the
Z16HD+: (See Figure 4-4 and Figure 4-5 for module location)
• A1, A2, A3 and A4 - Front, Z-Plane A
• B1, B2, B3 and B4 - Front, Z-Plane B
• C1, C2, C3 and C4 - Front, Z-Plane C
• D1, D2, D3 and D4 - Front, Z-Plane D
• A5, A6, A7 and A8 - Rear, Z-Plane A
• B5, B6, B7 and B8 - Rear, Z-Plane B
• C5, C6, C7 and C8 - Rear, Z-Plane C
• D5, D6, D7 and D8 - Rear, Z-Plane D
4.2.2.4 Z-Plane Combiner Board
The Combiner Board receives the outputs from the 8 PAs and combines them in two 4
Way isolated Wilkinson combiners, whose outputs are then combined in a 2 way
Wilkinson combiner.
All of the isolation loads for a Z-Plane are located on another board called the Isolation
Board for better heat dissipation and easier access. The Isolation boards are located on
each side of the Power Blocks for a total of 4. The Isolation Board also contains RF
switches which can switch out a faulty PA without causing a severe system imbalance,
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