已知信号f(t)的波形如图所示,则=()
A: 0
B: δ(t)-δ(t-2)
C: 2δ(t)+2δ(t-2)
D: 2δ(t)-2δ(t-2)
A: 0
B: δ(t)-δ(t-2)
C: 2δ(t)+2δ(t-2)
D: 2δ(t)-2δ(t-2)
举一反三
- 已知信号f(t)如图所示,其表达式是()[img=268x156]17e0c04ffc82c35.png[/img] A: ε(t)+2ε(t-2)-ε(t-3) B: ε(t-1)+ε(t-2)-2ε(t-3) C: ε(t)+ε(t-2)-ε(t-3) D: ε(t-1)+ε(t-2)-ε(t-3)
- 【单选题】已知f 1 (t)=tε(t),f 2 (t)=ε(t)-ε(t-2)试求y(t)=f 1 (t)*f 2 (t-1)*δ’(t-2) A. (t-3)u(t-3)-(t-5)u(t-5) B. (t-2)u(t-2)-(t-5)u(t-5) C. (t-3)u(t-3)-(t-4)u(t-4) D. (t-3)u(t-2)-(t-5)u(t-3)
- 信号f(t)=2ε(t+1)-3ε(t-1)+ε(t-2)的波形图为
- 一振幅为A、周期为T、波长为λ的平面简谐波沿x轴负向传播,在x=λ/2处,t=T/4时振动相位为π,则此平面简谐波的波动方程为()。 A: y=Acos(2πt/T-2πx/λ-π/2) B: y=Acos(2πt/T-2πx/λ+π/2) C: y=Acos(2πt/T+2πx/λ+π/2) D: y=Acos(2πt/T+2πx/λ-π/2)
- 一振幅为A、周期为T、波长为λ平面简谐波沿X负向传播,在X=(1/2)λ处,t=T/4时振动相位为π,则此平面简谐波的波动方程为:() A: y=Acos(2πt/T-2πx/λ-1/2π) B: y=Acos(2πt/T+2πx/λ+1/2π) C: y=Acos(2πt/T+2πx/λ-1/2π) D: y=Acos(2πt/T-2πx/λ+1/2π)