Asynchronous phase comparator for characterization of devices and PMU calibrator

This paper reports the recent progress in developing and implementation of a new asynchronous digital phase comparator suitable for phase error characterization of voltage ratio devices and calibration of functional elements of PMU calibrators. The phase error of the proposed digital comparator is below 300 nrad at 50 Hz and 100 μrad at 100 kHz with applied voltages ranging between 500 mV and 3 V. The phase error of cables and connectors is 4 μrad at 1 MHz. The system is a relevant tool for phase-frequency characterization of devices employed also for specific wideband power measurements.