Precision of the Sinefitting-Based Total Harmonic Distortion Estimator

Abstract

An analytical expression for the standard deviation of Total Harmonic Distortion (THD) estimation is derived. It applies to the case where the estimator uses sine fitting. It is shown that, in common circumstances, it is inversely proportional to the actual value of THD, the signal-to-noise ratio and the square root of the number of samples. The proposed expression is validated both with numerical simulations and an experimental setup using a Monte Carlo procedure.

Keywords

• Total Harmonic Distortion
• noise
• sine wave fitting