The THD measurements at voltage levels 2 - 2.83 V were carried out with High Pass Filter "on" (2nd order Butterworth type, 500 Hz cutoff, HPF2-500)
The THD measurements at voltage level 4 V were carried out with High Pass Filter "on" (2nd order Butterworth type, 800 Hz cutoff, HPF2-800)
The THD measurements at voltage levels 5.6 - 8 V were carried out with High Pass Filter "on" (4th order Butterworth type, 800 Hz cutoff, HPF4-800)