Measuring device for determining extent and direction of relative movement between two objects having modulation section

摘要

A measuring device is disclosed which is capable of exhibiting increased resolution. The device is constructed to detect a moire fringe produced by two scales as A and B phase signals different in phase by 90 DEG and to convert each of the phase signals into a frequency-modulated signal by means of a carrier of a predetermined cycle to digitally read out the deviation of a phase varied with relative movement between both scales.