Shock: Damage Boundary C For trapezoidal pulses, the programmer is a constant force pneumatic cylinder. The g-level of the trapezoidal pulse is controlled simply by adjusting the com pressed gas pressure in the cylinder. The Av is controlled by adjusting drop height A Shock Testing Machine (1)Shock: Damage Boundary c. For trapezoidal pulses, the programmer is a constant force pneumatic cylinder. The g-level of the trapezoidal pulse is controlled simply by adjusting the compressed gas pressure in the cylinder. The ∆V is controlled by adjusting drop height. A Shock Testing Machine (1)