CHPA SERIES
1-4
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1.3 Major Subsystems and Their Functions
The CHPA (Figure 1-1) is packaged in an 8.75-inch-tall slide-mounted drawer suitable for
standard 19-inch rack mounting. This enclosed assembly houses both the RF and power supply
sections. The overall amplifier enclosure measures approximately 19" (w) x 8.75" (h) x 24" (d),
plus fan and external air duct adapters, and weighs approximately 90 lb.
The RF section includes the TWT (traveling wave tube), SSIPA (solid-state intermediate power
amplifier) with integrated PIN diode attenuator, input/output isolation circuits, RF detectors,
and output filter.
The power supply section includes the power factor correction, power processor, and high-
voltage regulation circuitry as well as monitor and control circuitry.
Microprocessor circuits provide automatic sequencing to control both CHPA operation and
continuous monitoring of critical parameters.
The front panel of the unit serves as the primary user interface housing all monitor and control
functions including a type “N” RF connector to sample and measure output RF power.
Protection circuits are included to permit safe, efficient, and reliable operation of the CHPA.
Detailed specifications for the CHPA are provided in Appendix A of Chapter 8,
“Supplementary Data.”
1.4 Technical Description
1.4.1 RF
Subsystem
A conservative, field-proven approach is used in the CHPA RF subsystem. The RF block
diagram (Figure 1-2) identifies all major circuit elements for this technical description.
Figure 1-2. CHPA RF Diagram