AC Estimate
The DC estimate is subtracted from the waveform, and a Hanning window is applied to give a processed waveform. The RMS voltage is calculated with the following equation:
sqrt ( [Σ processed waveform[i]2] / [numPoints × enbw × cg2] ),
where the equivalent noise bandwidth (enbw) for the Hanning window is 1.5, and the coherent gain (cg) is 0.5.
This algorithm minimizes the effect of an uneven number of waveform cycles in the measurement, which could arbitrarily increase or decrease the RMS value.
Units
Volts RMS