题目内容

段落翻译（手写拍照上传）：Although there is a wide variety of EDM instruments available with different wavelengths, there are basically only two methods of measurement employed which may divide the instruments into two classification as electro-optical (light waves) and microwaves (radio waves) instruments.

查看答案

搜索结果不匹配？点我反馈

更多问题

段落翻译（手写拍照上传）：They function by sending light waves or microwaves along the path to be measured and measuring the time differences between transmitted and received signals, or in measuring the phase differences between transmitted and received signals in returning the reflecting light wave to source.

段落翻译（手写拍照上传）：Modern EDM instruments are fully automatic to such an extent that, after the instruments, set up on one station, emits a modulated light beam to a passive reflector set up on the other end of the line to be measured. The operator need only depress a button, and the slope distance is automatically displayed.

What are EDM instruments?（用英语回答，手写拍照上传）

What is the basic principle of EDM instruments?（用英语回答，手写拍照上传）