Implementation of a Digital Radio Frequency Memory in a Xilinx Virtex-4 FPGA

Abstract: Digital Radio Frequency Memory (DRFM) is a technique widely used by the defense industry in, for example, electronic countermeasure equipment for generating false radar targets. The purpose of the DRFM technique is to use high-speed sampling to digitally store and recreate radio frequency and microwave signals. At Saab Bofors Dynamics AB the technique is used, among others, in the Electronic Warfare Simulator (ELSI). The DRFM technique is implemented in a full-custom ASIC circuit that has been mounted on circuit boards in ELSI. Today, the progress in the programmable hardware field has made it possible to implement the DRFM design in a Field Programmable Gate Array (FPGA). The FPGA technology has many advantages over a full custom ASIC design. Hence, the purpose of this master's thesis has been to develop a new DRFM design that can be implemented in an FPGA, using a hardware description language called VHDL. The method for this master's thesis has been to first establish a time plan and a requirement specification. After that, a design specification has been worked out based on the requirement specification. The two specifications have served as a basis for the development of the DRFM circuit. One of the requirements on the design was that the circuit should be able to communicate through an external Ethernet interface. A part of the work has, thus, been to review available external Ethernet modules on the market. The result is a DRFM design that has been tested through simulations. The tests shows that the design works as described in the design specification.