Research Of Digital Intermediate Frequency Technology On FPGA

The Soft-Defined Radio (SDF) now is a very hot research field in Radio technology. Nowadays, considering the condition of the hardware, the wide band band-pass sampling digital structure in intermediate frequency is mostly used in SDF system. So the technology of digitized intermediate frequency becomes the key technology. And now the Field Programmable Gate Arrays (FPGA) has become more and more important in digital signal processing. The aim of this article is to combine the two things to implement the digital intermediate frequency processing on FPGA.Firstly we study the basic knowledge of SDF and its structure. Secondly we study the related basic theory: signal sampling theory, multi-speed signal processing theory, filter design theory, and digital algorithm in FPGA. On the basis of these studies, considered the application condition, we put forward the intermediate frequency processing system, which is suitable to FPGA implement. It uses the multi-partitions structure to realize the six times abstract, and uses FIR filter to realize the anti-frequency disturbing filter. Then we simulate the system in Matlab, to check the system feasibility. Thirdly we use Verilog-HDL to program the system, and implement it in the FPGA chip. The system includes mixer module, the abstracting filter module and the signal producing module.Finally, the function of the digitized intermediate frequency system is verified in both software and hardware. The result shows the original request is well satisfied.