COMPENSATION CIRCUIT FOR DETECTION SIGNAL OF OPTICAL TYPE ENCODER

摘要

PURPOSE:To make an encoder small in size and also to prevent an effect due to nonuniformity in the characteristics of light-emitting elements by a method wherein a peak value of a position signal detected for each phase is detected by a switching means, signals from the switching means are averaged and a signal thus obtained is used as a reference signal. CONSTITUTION:This circuit has a timing detector 6 which changes over the voltage of a position signal detected for each phase by the timing of the phase of the detected voltage and a switching means 5 driven by the detector 6. Signals from the means 5 are averaged and a reference signal thus obtained is used for compensating each phase. Since a reference voltage is prepared by detecting peak values of the signals detected for each phase, by the switching means 5, and by averaging the values and is used for compensating the phase in this way, it is unnecessary to provide an optical system for the reference signal and an effect due to nonuniformity in light-sensing and light-emitting elements or to a change with time thereof is prevented substantially.