某系统的系统函数为H（s），若同时存在频响函数H（jω），则该系_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题单项选择题

某系统的系统函数为H（s），若同时存在频响函数H（jω），则该系统必须满足条件（）。

A.时不变系统

B.因果系统

C.稳定系统

D.线性系统

答案

参考答案：C

补全对话，情景问答

阅读下面对话，从方框内7个选项中选择5个恰当的句子完成此对话，并将其序号填入题前括号内。

A. I've gone to a paper factory.
B. That would be fine.
C. That's terrible!
D. Yes, of course.
E. Good idea!
F. The river has become very dirty.
G. I've been to a paper factory.

A: Where have you been, Fang Li ? I called you, but you weren't in your office.
B: 1.
A: What did you do there?
B: I found out that the factory was pouring waste water into the river near it. 2.            Lots of fish have died.
A: 3.
B: Do you think "Greener China" can do something?
A: 4.             We can write a story about it to the TV station and the newspaper.
B: 5.               Businessmen are afraid of newspapers and TV stations.

多项选择题

干扰素的主要生物学作用有（）.

A.抗增殖作用

B.抗血管生成

C.增强细胞表面抗原的表达

D.调节细胞分化

E.抗病毒作用