模拟和数字(IIR)滤波器的CAD

本文以布特沃思型滤波器为例,提出了统一设计模拟和数字(IIR)滤波器传递函数的CAD方法,并给出了程序设计框图、设计举例和结果。只要给定滤波器的特性指标(通带最大衰减A_(max)、阻带最小衰减A_(max)、通带边界频率f_P、阻带边界频率fs及采样频率fa)就能迅速得到滤波器传递函数的系数、幅频值、相频值及幅频曲线。运用计算机设计方法,避免了设计过程中的繁复计算,大大加快了设计速度,并提高了设计精度。

A Computer Aid Design of Analog and Digital (IIR) Filter

Taking Butterworth filter as an example, this article presents a method of CAD for transfer function of analog and digital filter, and gives the block diagram, the designing examples, and results. Given the filter specifications (passband edge frequency f_p, stopband edge frequency f_s, maximum attenuate in passband A_(max), minimum attenuate in stopband A_(min), and sample frequency f_a), the coefficients of transfer function of filter, amplitude frequency value, phrase frequency value, and, amplitude frequency curve can soon be obtained. With computer aid design, complicated calculation in designing procedures can easily be eliminated, designing speed greatly increased, and precision improved.