操作冲击电压的标准波形是（）波 A: ±200/2500 μs B: ±250/2500 μs C: ±250/2000 μs D: ±200/2000μs

The project, ( ) by the end of 2000, will expand the city's telephone network to cover 1, 000, 000 users.

中国大学MOOC: On Hollywood’s , there are more than 2000 Star Medals with Hollywood celebrity name.

某调频波S(t)=20cos(2000πt+8sin400πt)，信号的带宽为（）

The 2000’s has been an era of great change in the movie and technology industries, and more change is sure to come quickly.

如果要对信号[img=133x18]1802df8bddd8844.png[/img]进行采样并在接收端进行重建,则最低的取样频率等于_______。‍ A: 1000rad/s B: 2000 rad/s C: 500 rad/s D: 4000 rad/s

When did English appear as a language spoken by few people A: In Julius Caesar's time. B: In Shakespeare's time. C: 2000 years ago. D: 2500 years ago.

设[tex=0.786x1.0]b4HkKtHXeHofHX/gJc8Agg==[/tex]系统以2000 b/s的比特率传输 [tex=2.643x1.0]vwqXC8qe7Fd6HD+1lhbACg==[/tex]调制信号的带宽为2000 Hz ,[tex=0.786x1.0]sHo1pKm+gjxjcUAJjHrarQ==[/tex]系统以2000 b/s的比特率传输[tex=2.643x1.0]9f12DpJoKN57T/CateG4gA==[/tex]调制信号的带宽为1000 Hz.试问 : 哪个系统更有效? 

2.5G（SDH）设备最多能接入（）个2Mbt/S信号。 A: 1000 B: 1008 C: 1800 D: 2000

China's first manned spacecraft was launched in _____ with the astronaut, Yang Liwei, on board? A: 1973 B: 2000 C: 2003 D: 2013