PURPOSE: To improve the response of arithmetic operation by calculating current wheel speed from the time difference between current calculation time and the time of an edge having the same polarity in a time pair and the number of pulses generated within the time difference.
CONSTITUTION: When the edge of the current calculation time has the same polarity with the edge of last calculation time, the wheel speed can be computed from the time difference between both calculation time values and the number of pulses. When the edge of the current calculation time has the opposite polarity from the edge of the last calculation time, on the other hand, the edge of a last calculation time which is a half pulse precedent is utilized. The edge is led or trailed, so time having the same polarity in a time pair of TD and TU stored as to the last arithmetic time is used in either case to perform current arithmetic operation.
YANO TETSUNORI
SAKAI KAZUNORI
TOYOTA MOTOR CORP
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