| 摘要 |
1,043,721. Monitoring distance measuring systems. ELLIOTT BROS. (LONDON) Ltd. Jan. 10, 1964 [Jan. 16, 1963], No. 1986/63. Heading H4D. In distance measuring equipment of the kind wherein transmitted and corresponding received echo energy (either electromagnetic or acoustic, pulse or C.W.) is compared to give a parameter indicating the return time of the energy, and thus, the distance of the reflecting object, a second receiver is provided whereby a second like parameter may be simultaneously derived for comparison with the first derived parameter to derive any difference therebetween and monitor said equipment. In the arrangement shown, energy from transmitter 1 is reflected by object 3 and fed to normal receiver 5, and, via a delay means 7 which introduces a delay representing a known distance, to monitoring receiver 6. A signal representing the distance of the object 3 is produced by distance computer 8 and fed, via line 12, to display means, and also to comparison means 10. The monitoring receiver 6 also provides a distance signal from computer 9 which is fed to comparison means 10. The comparison means is biased by unit 11 to take account of the delay introduced by means 7, such that it only gives an output to actuate alarm 14 when the two receivers 5 and 6 fail to give identical target distances, ignoring the artificial distance introduced by delay means 7. The delay means 7 and biasing unit 11, are provided such that the comparison means 10 produces an alarm actuating signal when both receivers fail to give an output.
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