| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly accurate magnetic type encoder which can remove harmonic components of odd orders. SOLUTION: In a magnetic type encoder, first and second magnetic field detection units 2 and 3 which are respectively provided with permanent magnets 21 and 32 mounted in the axial direction of a rotor 1 and magnetic field detectors 23 and 33 arranged on stators 22 and 23 are linked through gears 24 and 34 and the gear ratio of the gears 24 and 34 is set in ratio so that the number of revolutions of the second magnetic field detection unit 3 is odd times as much as the number of revolutions of the first magnetic filed detection unit 2. A signal processing circuit 4 is provided with differential amplifiers 41-44 to process a differential signal between the magnetic field detectors 23 and 33 respectively disposed on the two magnetic field detection units 2 and 3, a signal shaping circuit 45 to shape a differential signal from the second magnetic field detection unit 3 with the speed thereof increased by the gears 24 and 34 and an angle detection circuit 4 to correct a differential signal of the first magnetic field detection unit 2 by a signal obtained by the signal shaping circuit 45.
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