Signal processing apparatus for encoder

摘要

After cyclic original signals generated from a sensing element of an encoder are converted into digital signals, positions P(0) to P(n) in one period are obtained for each given period by means of a digital interpolator. If position data obtained immediately after a zero cross point is detected are P(0) and P(n) and if speed is fixed, an object should move on a straight line from a position P(0) to a position P(n). An actual detected position data P(m) is deviated from this straight line by D(m). This detection error D(m) and the detected position data P(m) are combined and stored in advance as reference data, and correction is carried out using the reference data every time position data is detected by the digital interpolator. <IMAGE>