【单选题】已知 判断该信号是否是周期信号,并确定其周期。
【简答题】如图4.3.3所示,已知输入时钟频率为20MHz(周期为50ns),希望得到一个输出信号PF,该信号为周期性输出信号,重复周期为150ns,其中高电平时间为50ns。请用D触发器和基本门电路实现。
【单选题】下列各项中,在我国具有最高法律效力的是( )。
【单选题】下列各项中,在我国具有最高法律效力的是( )
【单选题】已知一脉冲信号其周期为1us,经过一个10分频器后,输出脉冲的周期为()。
【单选题】下列各项中,在我国具有最高法律效力的是()
【单选题】已知一脉冲信号其周期为10uS,经过一个四分频器后,输出脉冲的周期为()。
【单选题】Passage Two 第19题
A.
People should take in less fat as they can.
B.
It is the reason for peoples obesity.
C.
It is useless for people's health.
D.
It adds a burden to people's heart.
【单选题】Passage Two Questions 19 to 22 are based onthe passage you have just heard. Question 19
A.
It contains one paragraph of introduction.
B.
It contains four paragraphs of evidence.
C.
It consists of two sides of the argument.
D.
It contains two paragraphs of the conclusion.