4. Phenomena affecting AC voltage measurements

4.1 Harmonics of the signal to be measured

Techniques for generating alternating sinusoidal signals very often require the superimposition of harmonics on the useful signal. The amplitude of these harmonics, which remains low compared to that of the fundamental component, decreases as the order increases. These components can be assimilated to disturbances, which are referred to as "series-mode interference components".

The instantaneous value of a signal altered by harmonic-frequency components of the fundamental is written as :