The THD measurements at distance of 315 mm and voltage levels 2 - 2.83 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 500 Hz cutoff, HPF2-500)
The THD measurements at distance of 315 mm and voltage levels 4 - 8 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 800 Hz cutoff, HPF2-800)