| 摘要 |
PURPOSE:To enable use over the entire angle range from 0 deg. to 360 deg. by using a code disk which has code tracks less than the bits of an output digital signal and an A-D converter. CONSTITUTION:When the pattern of a track 40 of the code disk 12 is read through the transparent window 44 of a fixed slit 13 through a light source 10 and a light receiving element 14, a triangular wave analog electric signal which is symmetrical about 1 180 deg. midpoint position is obtained from an output line 16. This analog electric signal is inputted to the A-D converter 19 through a differential amplifier 33 and then digital outputs are obtained from output lines 19c, 19b, and 19a respectively. In this case, the code disk 12 is provided with code tracks less than the bits of the output digital signals to perform detection over the entire angle range of 360 deg..
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