Analysis And Design Of The Signal Processing System For Ultrasound Flaw Detector Based On FPGA

In ultrasonic flaw detection system, due to the complex and volatile environment, there is a lot of practical application of interference and noise, detector and the target of the intersection of attitude can not be fully predicted, resulting in target echoes produced detector for strange and distorted echo characteristics stability deteriorated, affecting the target detection and recognition. Therefore, the return of the detector effective filtering is essential. In this paper, FPGA (field programmable gate array integrated circuit) features high-speed programmable, FIR (Finite Impulse Response) digital filter is designed to filter the interference signal using FPGA. This article reads as follows:1 The elementary theory of FIR digital filter and the digital signal process and the applications of the digital signal process were analyzed, through comparing the design method of sixteen-tapped low-pass FIR filter, thinking from the optimization of this systems, this article use FPGA,distributed arithmetic algorithm,series-parallel combination to finish this design.2 A scheme of hardware implementation is worked out using distributed arithmetic algorithm. As the scale of the LUT(Look Up Table)is so large in the distributed arithmetic algorithm, the thesis reduces half of it with the use of pre-add and the symmetry characteristic of linear FIR filter. As the FPGA has the character of high-speed and programmable , it is suitable for the distributed arithmetic algorithm. After comparing the methods of FPGA,DSP(Digital Signal Processor),SCM(Signal Chip Micyoco), the design uses FPGA to realize.3 Through comparing the speed and resource occupancy percent of the serial and parallel design methods of four-tapped low pass linear FIR filter, the design method that is called half serial is used to design the sixteen-tapped low pass linear FIR filter. The FIR filter system is divided into five function modules. VHDL language is used to finish all functional modules. Finally the design of the FIR filter is finished.4 At last,a sixteen-tapped low-pass FIR filter is designed, and the simulation is designed using QII8.0, the simulation result proved the design to be right. The design is also analyzed with MATLAB, and the wave picture getting from MATLBA proved that the function of the design is effective.