For the surveillance(警戒) radar, the target receives energy from only a portion of the beam(波束), thus the R–4 relation(关系) between transmitted and received power levels(功率电平).
举一反三
- 二次监视雷达解释正确的是 A: second surveillance radar B: secondary surveillance radar C: primary surveillance radar D: precision approach radar
- Of the sun’ s total output of radiant energy, the earth receives （） A: one tenth B: one millionth C: all that comes from the surface of the sun D: a very small portion
- I could see from his face that he__ bad news. A: had received B: receives C: received D: has received
- The energy transmitted to the wheels to propel the vehicle's motion comes from at least two different energy conversion devices.
- In terms of social status, people’s language will reflect the power relation between them.