I did a piezoelectric test with a digital oscilloscope and when I hit it with my hand only once I saw it rise and fall several times instead of just once. Immediately after the impact was stopped, the output was stable, but during the impact, it seemed as if there were several impacts. Does anyone know why? Why are multiple outputs recorded? And what is the solution?

The image on the left of each peak shows the increase in output during each hit. In the enlarged image on the right, you can see the image on the left that the voltage has reached its maximum and minimum in each stroke about 10-12 times.