
A.
B.
C.
D.
[单选题]A.1B.CPC.脉冲信号,频率为时钟脉冲频率的1/2D.0
[单选题]A.-1.475,142.32B.-1.475,284.64C.1.475,-284.64D.1.475,-142.32
[单选题]A.-1.475,142.32B.-1.475,284.64C.1.475,-284.64D.1.475,-142.32
[单选题]A.σ≤[σ],τ<[τ]B.C.D.
[单选题]A.B.C.D.以上A、B、C均不成立
[单选题]A.电路的功率因数一定变大B.总电流减小时,电路的功率因数变大C.总电流减小时,感性负载的功率因数变大D.总电流减小时,一定出现过补偿现象