Harris DX 25U, Техническое руководство

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all active amplifiers deliver combinations of equal and binary
weighted RF voltages.
G.2.2.1
Binary Steps
The RF amplifier modules used in binary step positions are
identical to all other RF amplifier modules, and are interchange-
able. The differences in binary steps are all on the Binary Com-
biner/Motherboard. The Binary steps are: the 1/2 Step B7 (RF
91); the 1/4 Step B8 (RF 92); the 1/8 Step B9 (RF 93); the 1/16
Step B10 (RF 94); the 1/32 Step B11 (RF 95) and the 1/64 Step
B12 (RF96). (Recall that these are RF voltage, NOT power
steps).
The fractional Binary Steps are obtained by operating these
amplifier modules with a combination of reduced supply volt-
ages and different combiner transformer turns ratios. As the steps
become smaller, there are more turns in the combiner transformer
primary windings.
In addition, four of the Binary steps (1/2, 1/4, 1/8, and 1/16) have
tapped transformer primary windings for fine adjustments in step
amplitude. The tap positions depend on operating frequency and
are selected with P30, P31, P32, and P33. Tap positions are
shown in the Frequency Determined Components chart in SEC-
TION IX, Diagrams.
G.2.2.2
DC Supply Voltages
All Big Step amplifiers, RF81-RF90, operate from the +230
VDC supply which is fed to the Binary Combiner/Motherboard
at terminals E7 and E3.
The 1/2 Step B7 and the 1/4 Step B8 amplifiers operate at +115 VDC.
This is fed to the Binary Combiner Motherboard at terminal E4.
The 1/8 Step B9, the 1/16 Step B10, the 1/32 Step B11 and the
1/64 Step B12 amplifiers operate at +60 VDC which is fed to the
Binary Combiner/Motherboard at E5/E6.
DX-25U
G-2 888-2297-002 12-12-94
WARNING: Disconnect primary power prior to servicing.