[关键词]
[摘要]
滤波网络传输函数的零点、极点位置对滤波性能起着决定作用。全极点滤波器的所有衰减极点都位于DC和∞处。如果将传输零点放在S面有限频率处,则会形成特殊频率响应:虚轴上(实频)的传输零点,可形成准椭圆函数的陡降幅频响应;而实轴上(虚频)的和复数(实部非零)传输零点则起到类似时延均衡网络的作用,实现线性相位传输响应。在对不同文献关于传输函数的理论表述进行分析后,总结了传输函数、特征函数以及滤波网络综合中的一些重要概念,给出了几种典型函数的极点分布图对比,提供了几种运用特殊的传输零点放置来实现特殊滤波响应的设计应用。
[Key word]
[Abstract]
Poles and zeros of the transfer function play an decisive role for filter performance.For an all-pole filter,the transmission zeros(attenuation poles) are all located at infinite frequency and dc.Finite transmission zero locations can be used to realize special features such as quasi-elliptic(real frequency zeros)response,equalized delay,i.e.linear phase(real axis or complex zeros).Some of the important concepts for network synthesis are analyzed which considered as a good summary of those formulated in several classic references.Pole&zero pattern comparison of some typical transfer functions is given,as well as some useful design examples using pole&zero locating technique.
[中图分类号]
TN713
[基金项目]