已知码元速率为400波特,这里假设2FSK两功率谱主瓣刚好互不重叠。则2FSK的带宽为
A. 400Hz
B. 800Hz
C. 1200Hz
D. 1600Hz
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A constant force of 8.0 N is exerted for 4.0 s on a 16-kg object initially at rest. The change in speed of this object will be
A. 0.5m/s
B. 2m/s
C. 4m/s
D. 8m/s
A particle is in simple harmonic motion with period T. At time t = 0 it is at the equilibrium point. Of the following times, at which time is it furthest from the equilibrium point?
A. 0.5T
B. 0.7T
C. T
D. 1.4T
A subatomic particle when at rest typically exists for about 20 ns before it decays. A beam of such particles is created traveling at 0.60c with respect to the laboratory. How far might such a particle travel in the lab before it decayed?
A. 4.5m
B. 9m
C. 12m
D. 15m
在部分响应系统中,采用预编码和相关编码目的之一是
A. 无码间干扰
B. 引入受控的码间干扰
C. 减少抽判时的电平数目
D. 避免差错传播现象