Research On Some Key Problems Of Acoustic Inversion System Based On Arm + Fpga

The NAH(near-field acoustic holography)acoustic inversion system is a new type of intelligent detection system,which combines the characteristics of sound field structure and the identification and location of sound source.It is a hotspot of acoustic research in recent years.In the field of vehicle noise detection and diagnosis technology,the research of near-field acoustic holography and inversion control system is of great practical significance for the treatment and detection of vehicle noise pollution.However,there are many problems in the current acoustic inversion measurement device,such as huge processing system,complex operation and expensive price,which are difficult to be popularized and applied.In order to solve these problems,we are committed to research and explore a set of acoustic inversion system based on embedded system.Based on the combination of ARM microprocessor and FPGA chip,and based on the theory of multi sphere wave superposition addition(WSA)near-field acoustic holography(NAH),we will miniaturize the previous huge NAH acoustic inversion system,and realize the rapidity and convenience of acoustic inversion test through embedded system,which can indirectly reduce the cost of equipment and realize the engineering practicability of acoustic inversion test system.But in the process of researching this kind of embedded acoustic inversion system,it is difficult to break through several key problems: 1)When the NAH technology of multi virtual sphere wsa is used in hardware,the two-dimensional fast Fourier transform algorithm and generalized matrix inversion algorithm are difficult to realize;2)After the inversion calculation,it is difficult to display the reconstruction results of acoustic quantities accurately on the plane liquid crystal display(LCD)in three dimensions.In order to solve the above problems,this paper will combine the NAH technology,parallel structure,digital scaling method,pipeline design method and parametric design method of multi virtual sphere wsa,and design a parallel high-speed 32-point 2D-FFT processor based on FPGA and a high-order full rank matrix inversion processor,and a 3D image plane mapping display program based on arm to solve the above key problems.In addition,this paper basically determines the overall framework and control process of the inversion system,and completes the functional structure and implementation process design of each subsystem,which provides technical support and theoretical support for the specific implementation of the inversion system.The following is a brief summary of each chapter:Chapter 1 introduces the background of the project and the development of Nah,acoustic inversion system and two kinds of processors.Chapter 2 introduces the basic theory of this project,introduces the NAH technology of correlation wave superposition and the key problems to be solved in the hardware implementation,and clarifies the design goal of this paper.Chapter 3 introduces the overall hardware design structure of the project and the design structure,ideas and processes of each part of the hardware in the system.Chapter 4 and Chapter 5 introduce how to use Quartus II 13.0 software platform to design IP core of 2D-FFT algorithm and generalized matrix inversion algorithm,and show and analyze the design content and simulation effect.Chapter 6 introduces the experimental verification process of this study,through the relevant experimental platform to test the design effect,compare and analyze the test results with the simulation results of Modelsim,and draw the research conclusions.Chapter 7 summarizes the results of this whole paper and puts forward the problems to be solved.