| 摘要 |
An encoder includes a scale (20), a detector array (16) that includes a plurality of detectors, and a signal processor (38) configured to process and convert into positional information, an output signal from the detector array. The signal processor includes a first phase acquirer (32), a second phase acquirer (33), and a positional information acquirer (34) configured to acquire Sv as a position signal that represents a position of the scale. Sv satisfies Sv=A·¦1-B·¦2 where A and B are coefficients that satisfy A/B=n/m using integers m and n that satisfy |(m·P1-n·P2)|<|(P1-P2)|. ¦1 is a first phase acquired by the first phase acquirer, ¦2 is a second phase acquired by the second phase acquirer, P1 is the first modulation period, and P2 is the second modulation period. |
