4.Plot the waveform for a regular pulse and pulses one with poor low frequency response, one with poor high frequency response, one with overshoot ringing, one with undershoot ringing.

• 绘出下列五种波形：标准脉波，低频不足的脉波，高频不足的脉波，过冲震荡脉波，下冲震荡脉波。