| 摘要 |
PCT No. PCT/GB96/00236 Sec. 371 Date Jul. 31, 1997 Sec. 102(e) Date Jul. 31, 1997 PCT Filed Feb. 1, 1996 PCT Pub. No. WO96/24027 PCT Pub. Date Aug. 8, 1996The invention concerns pulse echo distance measurement and in particular a method and apparatus for calculating such a distance by sensing multiple reflections of a given pulse signal. By sensing multiple reflections, and not just the primary echo, internal time delays which would otherwise cause systematic errors may be simply eliminated and the multiple readings obtained may be utilized to provide system self-diagnostic checks, eliminate spurious information and provide an accurate measure of distance. A particular advantage of the method is that very small distances between sensor and target may be measured.
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