Design And Analysis Of FIR Filter In Radar Jamming System(Application Of FFA Cascade Structure)

With the rapid development of microelectronics technology and communication technology,radar is widely used in the defense and military fields,and plays a pivotal role in the modern electronic warfare.Research on radar jamming system is one of the important steps to improve the ability of electronic countermeasures.Radar jamming systems are often composed of many devices and modules,and FIR filters is one of the most important functional blocks in digital signal processing units.In this paper,the required FIR filter is designed using FFA cascade structure,based on a radar jamming system designed by a Institute of Electronics,combined with the principle of FIR filter.It is proved that the designed FIR filter satisfies the requirements of the radar jamming system,and the logical resource usage is consistent with the theoretical result,through the system simulation and result analysis.This paper studies mainly from the following aspects:(1)Starting from the working principle of the radar system,the common radar interference modes,such as distance interference,speed interference and multi-target interference,are analyzed.Combined with the design scheme of the radar jamming system,the main modules and devices of the system are analyzed,the working principle of the system is clarified,and the performance requirements of the required FIR filter are determined.(2)The principle and characteristics of several common FIR filter structures are compared and analyzed,and the parallel structure is studied,based on the basic principle of FIR filter.The commonly filter design methods,such as window function design method,frequency sampling method and other ripple approximation method are studied theoretically and characteristic,which provides theoretical support for FIR filter design.(3)In this paper,the FFA cascade structure is used to design the FIR filter.FFA cascade structure can greatly reduce the use of hardware resources,in the premise of ensuring the performance of FIR filter.For the FFA cascade structure,this paper starts from the CRT algorithm and the Winograd algorithm to study the FFA algorithm,and then,analyse the FFA cascade structure.(4)The design of the filter is determined by analyzing the technical requirements of the FIR filter.Complete the FIR filter design using Verilog HDL.Simulate and analyze the design by ModelSim,with the help of MATLAB.Simulation result shows that the function of designed FIR filter can meet the requirements,and because of the FFA cascade structure,the design can save a lot of logic resources,compared with the traditional structures.According to the compilation report of the Quartus II,the resource usage of the filter is consistent with the theoretical results.