| 摘要 |
PROBLEM TO BE SOLVED: To satisfy both of improvement in dispersion resistance and improvement in detection responsiveness without requiring a high-end CPU. SOLUTION: An updated rotational speed N<SB>new</SB>of a rotor 70 is calculated per a unit of updated pulse signal P<SB>new</SB>using a pulse interval ratio T<SB>ratio</SB>calculated from an updated pulse interval T<SB>new</SB>and a pulse interval T<SB>old</SB>at one rotation before in a newest tooth, and an average rotational speed NO calculated based on a total T<SB>all</SB>of pulse intervals for one rotation of the rotor 70 one rotation before, selected so that the newest tooth and the same tooth become the center, therefore, individual variation in relation to a pulse interval T such as dimensional variation when processing a tooth 72 is eliminated and also detection responsiveness for rotational speed is improved. Furthermore, the calculation of the updated rotational speed N<SB>new</SB>does not require a high arithmetic proficiency in a CPU such that the updated rotational speed N<SB>new</SB>is estimated from transition of movement average, but can be sufficiently processed within the range of the CPU proficiency for current vehicles. COPYRIGHT: (C)2011,JPO&INPIT
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