| 摘要 |
PROBLEM TO BE SOLVED: To provide a correction circuit of an encoder signal, capable of outputting interpolation division data having no deviation without generating a gap in a correction value, even when update of the correction value is switched from an invalid state into a valid state, with respect to a two-phase analog sine wave including periodical fluctuations in the offset, amplitude and phase. SOLUTION: An encoder for outputting position data 14a from an analog sinusoidal wave signal of orthogonal A-phase and B-phase has a constitution which includes a correction value calculating section 20; a speed determining section 21 for outputting a speed determination flag 21a; a correction value update determining section for invalidating a correction value update flag 22a, when the speed determination flag 21a has a high speed, and validating the correction value update flag when the speed determining flag has a low speed and an operation correction value 20a agrees with a signal correction value 23a; and a correction value update section 23 for updating by the operation correction value 20a, the signal correction value 23a used for signal correction in the valid case in accordance with the correction value update flag 22a, and holding the signal correction value, without updating in an invalid case. COPYRIGHT: (C)2011,JPO&INPIT
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