| 摘要 |
PROBLEM TO BE SOLVED: To provide a speed detection circuit for highly accurately detecting a speed in a small arithmetic circuit. SOLUTION: A speed detector includes: a memory for storing a trigonometric function to a temporary angle; a first register for storing a first coordinate of a motion object; a second register for storing a second actual coordinate obtained in next sampling; a rotation direction determination part for calculating the temporary coordinate on a straight line connecting a point obtained by rotating the second actual coordinate to a direction of a coordinate axis by only an angleθand an original point when making a rotation angleθfrom the first coordinate to the coordinate axis and determining a rotation direction to the second actual coordinate from the first coordinate based on signs of a temporary coordinate; and an arithmetic part for calculating a second coordinate in calculation obtained by the calculation of the first coordinate and the trigonometric function so as to approximate to the second actual coordinate and calculating the speed of the motion body based on the temporary angle corresponding to the trigonometric function at this time. COPYRIGHT: (C)2010,JPO&INPIT
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