| 摘要 |
An optical shaft angle encoder has a circumferentially extending data track (14) having alternating windows (16), and opaque spaces (17) between the windows. Each window and space between windows has substantially the same width along the track. An array of photodetectors (1-9) is provided adjacent to the data track, each having substantially the same width as a space or window and an LED illuminates the photodetectors through the windows. The areas of successive windows along the track are in a predetermined sequence which does not repeat around the track. The photo current due to illuminating the photodetectors in the array provides a unique indication of the angular position of the code wheel at essentially all times, including immediately upon startup of the encoder. There are interleaved arrays of odd and even numbered photodetectors.
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