Basic arithmetic operations; DFSWT; Frequency estimation; Harmonic distortion; Nonlinear loads Active power Filter; Arithmetic operations; DFSWT; Harmonic components; Low-power consumption; Nonlinear load; Power quality monitoring; Shunt active power filters; Active filters; Electric rectifiers; Estimation; Frequency estimation; Harmonic analysis; Harmonic distortion; Industrial electronics; Nonlinear analysis; Patient monitoring; Power quality