The THD measurements at voltage levels 2 - 4 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 1000 Hz cutoff, HPF2-1000)
The THD measurements at voltage levels 5.6 - 8 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 1500 Hz cutoff, HPF2-1500)