问题
单项选择题
.对于一阶环节，当输入信号X（t）=A时，输出信号Y（t）实际上沿其指数曲线上升，当Y（t）达到稳定值的（）处，所经历的时间其数值恰好为时间常数T。
A、0.368
B、0.382
C、0.618
D、0.632
答案
参考答案：D
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.对于一阶环节，当输入信号X（t）=A时，输出信号Y（t）实际上沿其指数曲线上升，当Y（t）达到稳定值的（）处，所经历的时间其数值恰好为时间常数T。
A、0.368
B、0.382
C、0.618
D、0.632
参考答案：D
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| One day, Peter went to see his doctor . "I am always tired when I 1 in the morning." he said. "Do you sleep well?" the doctor asked. "Well, not 2 . I dream so much. I have being like this for a long time." Peter answered. "Well, sometimes dreaming is good 3 us," said the doctor. "Maybe," Peter said. "But my trouble is 4 I always dream about hard work! Last night, as soon as I fell 5 , I dreamt that I went to the 6 to plant trees all night long! Then several nights ago, I dreamt that I was on an old 7 in a terrible storm at sea. We had to work for hours to stop the ship from sinking. It seems that, in my dreams I always have very difficult jobs to do." "What about the sleeping 8 that were given to you several days ago? Don't they work?" the doctor asked. "Yes, but not well. But if I don't take one, I will be awake all night." "Then try 9 before you go to sleep. 10 , listen to light music." the doctor said. | |||
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