| 摘要 |
PROBLEM TO BE SOLVED: To detect an origin by a simple structure by performing computation according to a rule of sensor signal change associated with scale shift. SOLUTION: The origin is detected by the following steps of: (S1) starting to detect the origin; moving the scale to generate a signal; (S2) detecting the maximum value Amax and the minimum value Amin of an analog signal A by detecting the analog signal A at time points where a digital signal DB rises and trails; (S3) calculating center voltage of the analog signal A by (Amax+Amin)/2; (S4) calculating SA=(current center voltage - center voltage of former sixth signal); and (S5) determining the rise of the digital signal DA with a pulse value satisfying SA > threshold LV1 as the origin. By thus determining a specific pulse edge of the digital signal as the origin, a highly accurate origin position can be obtained. COPYRIGHT: (C)2008,JPO&INPIT
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