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Abstract

The encoder includes a scale provided with a periodic pattern, a sensor relatively movable with respect to the scale and reading the periodic pattern to output analog signals each having a changing period corresponding to the periodic pattern and having mutually different phases, an A/D converter performing time-division analog-to-digital conversion on the analog signals output from the sensor to produce digital signals, and a phase detector detecting a phase from the digital signals. The encoder further includes a corrector calculating a correction value by using a relative movement speed of the scale and the sensor and the detected phase detected by the phase detector, and calculating a corrected phase from the correction value and the detected phase, and a position detector calculating a position in a direction in which the scale and the sensor are relativity moved by using the corrected phase.

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