PHASE SHIFT METER OF ELECTRICAL SIGNALS

Abstract

This paper examines theoretical foundations, measurement methodologies, and the practical realization of a phase shift meter designed to measure phase differences between signals of identical frequency but varying amplitudes. The measurement of phase difference between electrical signals is a fundamental task in electrical engineering, electronics, and information and communication technologies. Accurate determination of phase relationships is essential for synchronization in power systems, analysis of communication channels, and training of specialists.

The paper reviews existing approaches to phase shift measurement. Analog methods include phase detectors, balanced mixers, compensation techniques, and direct conversion schemes. Digital methods, implemented mainly on programmable logic devices, comprise correlation analysis, Hilbert transform, and quadrature techniques, offering flexibility and precision. Time-domain methods determine phase difference by measuring delays between zero crossings or characteristic points. Each approach has advantages and limitations, but together they form the basis for modern instrumentation.

The developed device operates in the frequency range of 30 Hz to 20 kHz, with a measurement span from 0° to 360°. Its conversion slope equals 8 mV per degree of phase difference. The lower input voltage limit is 0.3 V, while the upper boundary is defined by protective circuitry. The study showed that when analyzing the dependence of the phase meter’s output signal on the phase difference around 170°, the polarity reversal from positive to negative and vice versa occurred at the same phase values (170°–172°), defining a transition region of the signals that takes place without hysteresis. It was found that to ensure stable operation, interference and noise must be eliminated by employing a metallic enclosure.

Experimental results confirm the linearity and reproducibility of the results, demonstrating the suitability of the phase difference measurement device for both scientific laboratories and educational environments.