Multimeter and digital VFD Filter active at 400Hz (graph of operation)

[Kiriakos GR]

Several quality multimeter they come with VFD filter or this also described as Low Pass filter.

Filters are useful to suppress harmonics, and actually unwanted harmonics.
In the application of variable frequency drives (motor speed control units) at 400 Hz max operating frequency, any higher signal above 400 Hz mark this is unwanted.
Reliable voltage measurements should be made by Filter this set to active state.

In the market they are several VFD controllers, max operating frequency this can be 100Hz or 200Hz or 400Hz.
Most to all multimeter manufacturers they design or use digital filters them aiming 400 Hz systems.

Bellow there is a graph of operation of such a digital filter this used by HIOKI DT4282