By using one-dimension FDTD method we simulates the decay of double exponential pulse through the soil media, and its refractive time-domain wave shape is discussed in detail.

We accordingly propose to take the marginal decay curve (whose function is simple) as a criterion to check if an observed pulse could be taken as a candidate suffered from the Doppler effect.

Add the workpiece fixed in the coil, coil discharge at the moment have a damping pulse magnetic field decay, so that the loss of magnetic parts.