New multiplier-based phase measurement technique with improved tolerance to harmonic distortion

A high performance phase measurement technique, which can determine the phase even when the signals are distorted by harmonics, is presented. Here the fundamental phases of the two input signals are measured in parallel, relative to a pure sine wave generated from either input, and then their difference is taken to compute the actual phase shift. The proposed circuit utilizes analogue multipliers as phase detectors and offers accurate measurement over a reasonably wide frequency range.