| 摘要 |
PCT No. PCT/GB83/00237 Sec. 371 Date May 25, 1984 Sec. 102(e) Date May 25, 1984 PCT Filed Sep. 26, 1983 PCT Pub. No. WO84/01214 PCT Pub. Date Mar. 29, 1984.An apparatus for measuring displacement between two members subject to movement relative to one another. The apparatus includes a scale defined by spaced marks provided on one of the members. A light source is arranged to illuminate the marks, wherein light reflected from the marks constitutes light signals. A light-receiving device is provided on the other of the members for receiving at least two light signals reflected from the marks in predetermined phase relationship. A determining circuit is coupled for receiving the light signals and for determining the sense of direction of the relative movement of one of the members based upon the phase relationship of the two light signals. A single optical fiber is provided for transmitting the light signals between the light-receiving device and the determining circuit. Additionally, color-encoding means are located for color-encoding the respective light signals. The light-receiving device is arranged for combining the light signals into a combined light signal which is transmitted via the single optical fiber to the determining circuit. Color-decoding means are arranged between the single optical fiber and the determining circuit for color-decoding the combined light signal.
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