说明：  本人使用次数最多的分立元件滤波器软件,功能非常齐全,基本能想到的问题它都替你考虑到了,唯一缺点是不注册的话对极点数和阻值作了一定的限制
(I have the highest number of discrete components using filter software is very complete, it can basically think of the problem are taken into account for you, the only drawback is not registered, then made of poles and resistance to certain restrictions)