High precision phase measurement using adaptive sampling

Abstract

The conventional phase measurement techniques introduce error in the phase when the input signals are distorted by harmonics. A novel technique, known as adaptive sampling, for high-precision phase measurement is introduced. A digital signal-processing approach is used in this technique. The maximum sampling rate required for this technique is h+2 samples/cycle of the input signals, i.e. (h+2)f sampless, where h, is the highest harmonic present in the signals and f is the fundamental frequency of the signals. This sampling rate is way below the Nyquist sampling rate (more than 2hf samples/s) when h is a large number. In the adaptive sampling technique the sampling rate is started from three samples/cycle and then is gradually increased until the phase is correctly measured. This phase measurement technique has been verified using synthesized signals. >