Encoder signal processing device and encoder

An encoder signal processing device that performs signal processing on analog signals that are periodically generated according to movement of a measurement target, to thereby generate position data according to the position of the measurement target, the encoder signal processing device comprising:

• a position data acquisition unit that samples the analog signals to acquire the position data according to the position of the measurement target;
• an error data calculation unit that calculates error data on the basis of a difference between a predetermined number of pieces of position data among position data for one cycle acquired by the position data acquisition unit and ideal position data that assumes that the position moves linearly in one cycle;
• and
• a compensation unit that compensates the position data acquired by the position data acquisition unit on the basis of the error data calculated by the error data calculation unit,
• the error data calculation unit:
• calculating first error data on the basis of a difference between the predetermined number of position data sampled at first predetermined time intervals ΔTn in one cycle and the ideal position data, and defining the first error data as the error data,
• calculating second error data on the basis of a difference between position data sampled at second predetermined time intervals ΔTk in each of the first predetermined time intervals ΔTn and the ideal position data;
• and
• on the basis of error characteristics of the first error data and the second error data, when there is the second error data that is closer to a local extremum or inflexion point in the error characteristics than the first error data, change a time interval of the error data without increasing or decreasing the predetermined number of pieces of the error data by replacing the second error data closest to the local extremum or inflexion point in the error characteristics with any of the pieces of the first error data.