| 摘要 |
PROBLEM TO BE SOLVED: To achieve high accuracy in speed detection, even when machining errors exist in tooth parts or slits of a disk in a pulse pickup sensor. SOLUTION: The speed of a motor is determined on the basis of a time difference between the time (Ta), at which pulse signals detected by a magnetic sensor 6 from the same tooth part of a rotator 5 this time are generated and the time (Ta') at which pulse signals detected previous time are generated. A time/phase latching processing part 7 determines the pulse generation time (Ta) and the pulse generation phase (Pa) of the pulse signals (Sa), on the basis of pulse edge waveforms in synchronizism with the edge positions of pulse signals (Sa) detected by the sensor and timer signals. A buffer memory processing part 10 stores the pulse generation phase (Pa) as the previous pulse generation time (Ta'), each time the pulse generation phase (Pa) is extracted. A speed computation processing part 9 determines the speed of the motor, on the basis of a time difference between the pulse generation time (Ta') stored in the buffer memory processing part and the pulse generation time (Ta) detected this time. COPYRIGHT: (C)2008,JPO&INPIT
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