超声波测距外文文献加中文翻译-毕业设计.doc

附录A 英文原文
ULTASONIC RANGING IN AIR
G. E. Rudashevski and A. A. Gorbatov
One of the most important problems in instrumentation technology is the remote,contactless measurement of distances in the order of to 10 m in a problem occurs,for instance,when measuring the relativethre edimensional position of separate machine members or structural possibilities for its solution are opened up by utilizing ultrasonic vibrations as an information physical properties of air,in which the measurements are made,permit vibrations to be employed at frequencies up to 500 kHz for distances up to m between a member and the transducer,or up to 60 kHz when ranging on obstacles located at distances up to 10 m.
The problem of measuring distances in air is somewhat different from other problems in the a -pplication of the possibility of using acoustic ranging for this purpose has been known for a long time,and at first glance appears very simple,nevertheless at the present time there are only a small number of developments using this method that are suitable for practical main difficulty here is in providing a reliable acoustic three-dimensional contact with the test object during severe changes in the air's characteristic.
Practically all acoustic arrangements presently known for checking distance