Phase Measurement Performance Evaluation of Differential Sampling System

In this paper, we introduced a method to measure AC power. Here, phase measurement performance was evaluated from the following perspectives as zero phase and different angle stability, small angle accuracy. The results shown that the diffderential sampling system has a high accuracy, where the variety of zero is less than
$0.1\ \mu \mathrm{rad}$
in four days, the difference between differential sampling system and lock-in amplifier on small angle phase measurement is less than
$0.1\ \mu \mathrm{rad}$
, and the differential sampling system has a good stability in different angle phase measurement.