Words4EV.speak 1.0 (en)

The switching noise is a high-frequency noise (5-15 kHz), that is sometimes inaudible, low in level and emerging. It has a motor-harmonic or inverse harmonic-motor behavior; its pitch can increase or decrease when the engine rpm increases. It may be bothersome, shrill or very annoying depending on the engine setting or the auditive sensitivity of the person. It is similar to high-voltage line sound or tonal tinnitus. Switching is a sound of electromagnetic origin due to pulse width modulation devices.