Patent ID: 9568338
Date: 2017-02-14
CPC Classifications: G01D

Claim:
1. An encoder comprising: a sensor unit configured to output a detected signal based on positional information of a driven body; a positional information generation unit configured to generate the positional information as first positional information based on the detected signal which is output by the sensor unit; and an IIR filter unit configured to output second positional information obtained by performing filtering on the first positional information based on a predetermined filter coefficient, wherein the IIR filter unit includes a counter unit configured to store a value corresponding to a predetermined high-order digit of the first positional information, as a count value, an input unit configured to subtract the count value stored in the counter unit from the first positional information to thereby generate input information, a delay information storage unit configured to store an internal computation result based on the input information, as delay information, a computation unit configured to generate the internal computation result based on the delay information stored in the delay information storage unit, the input information, and the predetermined filter coefficient, and generates output information on which filtering is performed, an output unit configured to add the count value and the output information to thereby generate the second positional information, and a changing unit configured to change a value of the delay information based on a unit of change of the input information when the value of the delay information falls outside of a predetermined range which is set in advance, and changes the count value.