Technical Manual

A-6 ATLAS 4500 Multimode Station Technical Manual July 2016
792-825 MHz Receiver Module Appendix A - 700/800 MHz Circuit Descriptions
A.1.2.7 Exciter DC Supplies
The exciter is supplied a nominal 13.8 V through CN3-2. This input supply is then
distributed to IC1, IC4, IC9 and IC11.
IC1 is configured as a 1 MHz buck DC-DC converter and provides the main
regulated +5.2 VDC output. A shielded inductor is used to reduce fields.
IC9 is configured as a boost DC-DC converter and provides +25 V DC output for
the main PLL.
IC3 is a linear regulator regulating the +5.2 V supply down to +5 VDC for linear
circuits, A/D, RF amps etc.
IC30 and IC48 are linear regulators regulating the +5 V supply down to +3.3 V DC
for the synthesizers.
IC33 contains multi-circuit buck DC-DC converters and low drop out regulators
that provide +3.3 V, +2.5 V, +1.8 V and +1.2 V for various circuit sections in the
digital portion of the exciter including the FPGA, memory and DDS etc.
A.2 792-825 MHz Receiver Module
This section contains information on the following Receiver Module components:
• Frequency Synthesizer
• RX VCO Board
• Reference Clock
•Front End
• 90 MHz IF Section
• Receiver DC Supplies
A.2.1 General Description
The receiver module converts a low level RF signal from an antenna input to a 90
MHz intermediate frequency (IF) output for processing with the DSP RX board.
Low side injection is used in the upper 2 bands, High side injection in the 2 lower
bands. The module has a 30-W interface and 2 SMB connectors for RF input and
90 MHz IF output.