Feature

Equation

RMS value

$\text{RMS}=\sqrt{\frac{1}{n}}{\displaystyle \sum _{i=1}^n}{a}_i^2$

Variance

$\text{Variance}=\frac{1}{n}{\displaystyle \sum _{i=1}^n}{\left(a_i-\overline{a}\right)}^2$

Skewness

$\text{Skewness}=\frac{{\displaystyle {\sum }_{i=1}^n{\left(a_i-\overline{a}\right)}^3}}{\left(n-1\right){\sigma }^3}$

Kurtosis

$\text{Kurtosis}=\frac{1}{n}{\displaystyle \sum _{i=1}^n}{\left(\frac{a_i-\mu }{\sigma }\right)}^4$

Peak value

$\text{Peak}=\max \left|a_i\right|$

Peak to Peak

$\text{PeaktoPeak}=\max \left(a_i\right)-\min \left(a_i\right)$

Crest factor

$\text{Crestfactor}=\frac{\text{Peak}}{\text{RMS}}$

Shape factor

$\text{Shapefactor}=\frac{\text{RMS}}{\frac{1}{n}{\displaystyle {\sum }_{i=1}^n\left|a_i\right|}}$

Impulse factor

$\text{Impulsefactor}=\frac{\text{Peak}}{\frac{1}{n}{\displaystyle {\sum }_{i=1}^n\left|a_i\right|}}$