| 摘要 |
PROBLEM TO BE SOLVED: To enable highly precise origin detection superior in reproducibility. SOLUTION: Two-phase main signals A1 and B1 outputted from a detector 21 for a main track are supplied for an interpolating circuit 31 to generate two-phase interpolation main signals A1' and B1' having a phase difference corresponding to the pulse width of an origin pulse signal Z. Two-phase signals A2 and B2 for origin detection outputted from a detector 22 for a sub track are supplied for an interpolating circuit 32 to generate two-phase interpolation signals A2' and B2' for origin detection having a phase difference larger than the phase difference corresponding to the pulse width of the origin pulse signal. First and second interpolation pulse signals P1 and P2 interpolated in specific phase timings are generated from the interpolation signals A1', B1', A2', and B2', and the origin pulse signal Z is outputted when their phases are matched. COPYRIGHT: (C)2005,JPO&NCIPI
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