Macromodel of Precise Signal-Phase Meter

Abstract

This paper presents a precise macromodel of a signal-phase meter, which allows continuous phase measurement during simulation. It has been developed as a support tool during the design process of a signal-conditioning circuit for incremental position encoders. The development of a signal conditioning circuit requires precise measurements of small signal phases, amplitudes and offsets using the analog/digital circuit simulator. The phase measurement cannot be performed directly with a simulator, therefore an appropriate macro-model is needed for a circuit simulator. The structure of the signal-phase meter is based on the conventional signal-phase measuring method and is intended for the measuring of a cosine-signal phase with a known frequency. It recommends that the time variations of an input signal's parameters (amplitude, phase, frequency, and offset voltage) are slow and small as possible. Rapid change of a signal's parameters decreases the simulation result's accuracy. A macro-model's precision mainly depends on the chosen parameters for the macro-model and for the simulation. We show that with the proposed meter's model, the phase angle can be measured with an accuracy of more than ±0,02%.