A study of automatic measuring circuit suitable for very small phase difference measurement

In this paper, we propose an automatic measuring circuit suitable for the simplified very small phase difference measurement circuit. The proposed circuit consists of a J-FET, envelop detection circuit and microcontroller (Arduino). The experiment of automatic phase difference measurement is performed using proposed circuit and automatic amplitude adjustment algorithm. As a result, the error rate of phase difference measurement is ±0.03% or less at phase difference up to about 0.64 deg.