Research On Digital Automatic Gain Control And Sensitivity Time Control

In the modern battlefield, the radar receiver facing increasingly harsh electromagnetic environment. The signals which come into the radar receiver are not only target signal, but also the clutter and jamming signals, the signals superimposed on each other makes the receiver blocking, there may even damage the receiver. Therefore, the development of modern radar system to adapt to complex electromagnetic environment is research priorities.As an effective solution, Automatic Gain Control(AGC) technology has become a research hotspot.For this problem, the digital AGC system is quantitatively researched.In the study of digital AGC system, the algorithms of each module of system are designed based on identified indicators. Digital detector technology is researched based on Cascaded Integrator-Comb filter (CIC), the CIC filter is simulated and the performance of CIC filter is analyzed; the coordinate rotation digital computer (CORDIC) algorithm is studied, different modes of the circular coordinate system are analyzed, the CORDIC algorithm system formula is derived and orthogonal channels data processing mehtod based on CORDIC algorithm is gotted; the incremental PID algorithm is analyzed, the affect of the factors on results of PID algorithm is studied and simulation results show that the algorithm can produce rapid fluctuations in the signal response and fully filled with system design requirements; the fixed-gain tracking filter was discussed, theαβfilter method and the advantages and disadvantages are given in this paper, the conclusion that the filter has goog filter effect is gotted. The digital STC technology is also studied and Distance-Attenuation and Distance-Control voltage curves are obtained.Based on the theoretical analysis and simulation results, the digital AGC system hardware test platform is designed and production, and the digital AGC system is debugged in the platform. The CIC filter, CORDIC algorithm and incremental PID algorithm are completed with VHDL language and pipeline technology, and the theoretical analysis of the results are verified by experimentation data.Experimental results show that digital AGC syste based on CIC filter, CORDIC algorithm and incremental PID algorithm has mang admvantages, such as fewer resources are needed, outputs are stable. It can effectively protect the receiver, which is important for the receiver to identify or track targets. The research results can be widely used in mang radar systems, and it has a widely application.