119,83,36,47,( )
A.-37
B.-11
C.11
D.37
参考答案:B
解析:前两项之差等于后一项。则36-47=-11。故选B。
质量为4.0 ×103Kg汽车,发动机的额定功率P=40Kw,行驶过程中所受阻力为2.0×103N,则汽车能达到的最大速度为 m/s。
Although a given waveform may contain frequencies over a very broad range, as a practical matter any transmission system will be able to accommodate only a limited band of (1). This, in turn, limits the data rate that can be carried on the transmission (2). A square wave has an infinite number of frequency components and hence an infinite (3). However, the peak amplitude of the kth frequency component, kf, is only l/k, so most of the (4) in this waveform is in the first few frequency components. In general, any digital waveform will have(5) bandwidth. If we attempt to transmit this waveform as a signal over any medium, the transmission system will limit the bandwidth that can be transmitted.
(4)是()
A.frequency
B.energy
C.amplitude
D.phase