STEVAL-IME013V1(Ultrasound Pulser Waveform Demo)output waveforms has the sharp burrs.

[BBing.1]

I try to generate pulses using STEVAL-IME013V1.The power supply information is as follows:

• VDD=+5V DC
• VSS=-5V DC
• HVM=+10V DC
• HVM_CW=-10V DC

Actually the board can generate the preset waveforms by the power supply.Show as the figure.

But I am curious at the sharp burrs phonemon.The sharp burrs amplitude even exceeds HVP(10V).

How can I solve the problem?