| 摘要 |
PURPOSE:To reduce position errors due to the nonlinear characteristics of a position sensor by constituting a computing element by dividing the entire detection range of a position sensor into plural ranges, and approximating and distributing output linear characteristics to the entire detection range to plural linear characteristics. CONSTITUTION:The entire detection range of the optical position sensor 6 is divided into two, which are approximated and distributed to two linear characteristics Kab and Kbc. Then when a target tract demodulating signal is inputted, it is divided into two. If the target track demodulating signal is smaller than the track demodulating signal of an intermediate position, a target is inside of the intermediate part, so a proportional constant Kab is applied to find a sensor position signal. When the target track demodulating signal is larger than the track demodulating signal of the intermediate position, the target is outside the intermediate part, so a proportional constant Kbc is applied to calculate a sensor position signal. The sensor position signal which is found as mentioned above is outputted from the arithmetic unit 25 to a D/A converter 19. Consequently, superior linear characteristics are obtained by even an inexpensive device which has inferior linear characteristics.
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