THD Measurement by Multi-Frequency Synchronous Detection

摘要

Multi-frequency synchronous detection allows THD (Total Harmonic Distortion) measurement with the simultaneous presence of the analysed signal and other accompanying signals. These accompanying signals can be noise and/or periodic signal asynchronous to the analysed signal. In this paper, the principles for using of multi-frequency synchronous detection for THD measurement are presented. The influence of the simultaneous presence of the analysed signal and other accompanying signals has been analysed. Example simulations illustrating the above-mentioned considerations have been carried out.