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1??ü′ê ′?í¨??2¨?÷￡?FIR￡?Matlab·???;


Abstract
This paper analyzes the situation of application and development of digital filter technology home and abroad. It introduces the basic structure of a digital filter, discusses different design methods of FIR and IIR filter, and points out that the traditional design method of digital filter is not only complex but also of heavy workload, even adjustment of filtering parametrer is very difficult. So it brings forwad another design method of digital filter which based on the Matlab software and Modelsim software. This paper introduces the design method of a high Q value band-pass IIR filter which meets the given standard -- the pass band is 45-55Hz, with attenuation of less than 3db; the stop band is 40-60Hz with attenuation greater than 80db. It deeply analyzes the design features and principles of the filter system and the key technical in the design. Then it describs the use of Matlab in design and simulation of the bandpass filte design. In the end, the procedure was simulated on Modelsim. Simulation results of Modelsim and Matlab compared to make proof of the accuracy of the design. It is proved that the design can be accurate at the sixth decimal place, stable error is within one ten thousandth; The design has good portability and widely practical application. In different applications, according to different performance requirements of order, speed and accuracy, etc, the IIR filter coefficients can change flexibly to make up of IIR filter of arbitrary order; In addition, VHDL procedure can also make certain optimizations, according to the different actual situation, to achieve greater speed or conservation of FPGA resources.

Key words??digital filter FIR Matlab simulation