OFF-TRACKING SENSOR

摘要

PROBLEM TO BE SOLVED: To provide an off-tracking sensor which can reliably detect on-tracking and off-tracking even when noise components are contained in the signals obtained in a quadrant photodetector. SOLUTION: This sensor detects the difference in the phase of the binary signals of two systems obtained in the quadrant photodetector by dividing them into leading phase and lagging phase and calculates the phase differences between the leading phase and lagging phase by separating with their signs. Then the above phase differences are averaged and the phase differences caused by the noise are canceled. COPYRIGHT: (C)2006,JPO&NCIPI