Patent ID: 6707291
Filing Date: 2004-03-16
Classification: G01D

Abstract:
A rotary- type position detector device comprising:a coil section including at least one coil to be excited by an A.C. signal; a magnetism-responsive member rotationally movable relative to said coil section, wherein relative rotational positions between said magnetism-responsive member and said coil section varies in response to rotational displacement of an object to be detected and impedance of said coil is caused to vary in response to a variation in the relative rotational positions between said magnetism-responsive member and said coil section in such a manner that a voltage produced in said coil is caused to vary in response to a variation in the impedance of said coil dining the variation in the relative rotational positions within a predetermined rotational angle range; a reference-voltage generation circuit adapted to generate a predetermined reference voltage; and an arithmetic operation circuit coupled to said coil and reference-voltage generation circuit, said arithmetic operation circuit adapted to perform an arithmetic operation between said voltage produced in said coil and said predetermined reference voltage, so as to generate at least two A.C. output signals having predetermined cyclic amplitude functions as amplitude coefficients, the cyclic amplitude functions of the two A.C. outputâ€³ signals being different, in their cyclic characteristics, from each other by a predetermined phase.