文档介绍：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 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 plex 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 pared 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 additi