Technical Manual

A-6 ATLAS 4500 Multimode Station Technical Manual December 2016
380-520 MHz Receiver Module Appendix A - UHF Circuit Descriptions
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.2 380-520 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.
The receiver module consists of two circuit boards: A Voltage Controlled
Oscillator (VCO) board and an RX board with associated frequency synthesizers,
down converter, TCXO, filtering circuits and internal power supply circuits.
Receiver input frequency programming is achieved by using serial data connections
to an external controller. A serial flash IC contains synthesizer band, charge pump
settings and configuration data read by the Controller.