| 摘要 |
PROBLEM TO BE SOLVED: To reduce a weight and a power consumption by reducing a sensor, broadening a range, simplifying a processing circuit, and reducing the entire size. SOLUTION: The rotational speed sensing device of the rotator for an automobile includes magnetic sensors 21, 22 each for sensing the change of a periodic magnetic field in association with the rotation of a rotator 1 rotating synchronously with wheels for the automobile in which a magnetic element 11 having periodically changing magnetic properties, is arranged on an outer periphery, a signal processing circuit 23 for signal processing the change of the sensed periodic magnetic field, and an arithmetic circuit 3 for calculating the rotational speed of the rotator for the automobile. Further, the magnetic sensors 21, 22 each has two magnet impedance elements disposed so as to become a phase relation in response to the period of the change of the magnetic properties of the magnetic element 11. The signal processing circuit 23 has a magnet impedance magnetic detector 2 having one signal processing circuit for alternately switching and signal processing an output by switching means S1, S2. COPYRIGHT: (C)2004,JPO&NCIPI
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