【单选题】在利用DFT分析无限长非周期信号的频谱时,需要利用窗函数对时域信号进行加窗截短。窗函数的频谱具有什么特点?
A.
在相同的窗口宽度下,主瓣越宽的窗函数,旁瓣的衰耗越大
C.
在相同的窗口宽度下,主瓣越窄的窗函数,旁瓣的衰耗越大
【简答题】吾得 兄 事之 活用类别:________,解释:_________
【单选题】关于聚合物球晶描述中错误的是( )
C.
球晶在正交偏光显微镜下可呈现特有的黑十字消光现象
【单选题】______ private cars are bringing us convenience, they also cause more traffic accidents and pollution.
【判断题】在利用DFT分析无限长离散非周期信号的频谱时,泄漏现象和栅栏现象是不可避免的。
【单选题】Separate passwords for every account make()difficult for cyber criminals to hack you.
【单选题】发电机并网合闸命令需要在相角差为零之前的一个时刻提前发出所基于的考虑是:
D.
抵消断路器的合闸动作延时,保证合闸瞬间相角差为最小
【简答题】A.account for B.comprise up C.make up of D.consist of
【简答题】阅读理解 Some scientists say that animals in the ocean are increasingly threatened by noise pollution caused by human beings. The noise that affects sea creatures comes from a number of human activities.I...