1、 1 摘 要 本文分析了国内外数字滤波技术的应用现状与发展趋势，介绍了数字滤波器的基本结 构，在分别讨论了 IIR 与 FIR 数字滤波器的设计方法的基础上，指出了传统的数字滤波器 设计方法过程复杂、计算工作量大、滤波特性调整困难的不足，提出了一种基于 Matlab 和 Modelsim 软件的数字滤波器设计方法，完成了高 Q 值 50Hz 带通 IIR 滤波器的设计, 达 到了通带 45-55Hz，衰减小于 3db，阻带 40-60Hz，衰减大于 80db 的参数指标。文中深入 分析了该滤波器系统设计的功能特点、实现原理以及技术关键，阐述了使用 MATLAB 进行 带通滤波器设计及仿真的具体
2、方法。最后把整个设计方案用 VHDL 语言进行了描述并在 Modelsim 上仿真。Modelsim 与 Matlab 的仿真结果对比说明该设计准确性好，可精确到小 数点后六位，稳定后误差小于万分之一；可移植性强，在实际应用中，可根据不同的阶 数、精度和速度等要求对 IIR 滤波器系数进行灵活的修改，以实现任意阶数的 IIR 滤波 器。因此，该设计方法可靠性好，效率高，极大的减轻了工作量，有利于滤波器设计的最 优化。 关键词 带通滤波器；IIR；Matlab；VHDL；Modelsim 仿真; Abstract This paper analyzes the situation of appl
3、ication 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, e
4、ven 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 ban
5、d 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 fi
6、lte 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 flexib
