| 摘要 |
PROBLEM TO BE SOLVED: To accurately synchronize the measurement values of a rough resolution and a fine resolution spatially by obtaining the deviation between a rough position that is measured by comparing a rough position reading value with an ideal rough position by a fine wavelength position measurement value and an ideal rough position, and extracting the deviation between the maximum and minimum from the ideal rough position over a selected section. SOLUTION: When a calibration trigger 530 is activated, a calibration processing is started and a read head is moved relative to a scale over the entire scale. As the scale head is moved relative to the scale over a desired calibration range, a dense wavelength measurement circuit 540 monitors the fine wavelength phase position measurement value being generated by a transducer signal generation/processing circuit 590. Then, a controller 520 obtains an actual rough wavelength resolution absolute position corresponding to the rough wavelength phase position measurement value. A position value comparison circuit 560 compares the actual rough resolution absolute position with the ideal rough resolution absolute position to obtain a phase difference or a position error.
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