| 摘要 |
PROBLEM TO BE SOLVED: To provide a position detector which is low-cost and which can prevent the detection of position data by a tracking system at a high speed. SOLUTION: Two-phase analog voltages at sinθand cosθare input and changed into rectangular waves, a change in any one sign in detected, and counted values in one cycle are detected and latched. At the timing of a position-data sampling operation, the counted values in the cycle are latched, the ratio of the latched counted values is found, the counted value in a passage cycle from a movement start which is found separately is used as high-order data, and desired position data is obtained. At a low speed, a sinθvalue and a cosθvalue are multiplied by a cosϕvalue and a signϕvalue which are created separately, a sinθcosϕ-cosθsinϕ=sin(θ-ϕ) is computed, the position detector is changed over to a processing circuit of a follow-up control system by which a sin(θ-ϕ) value is approximated to 0, and a position signal is obtained.
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