声音简介
Passage 2
The echo sounder sends a radio signal from the bottom of the ship to the seabed, form which it is reflected. The time taken to receive the reflected signal is a measure of the depth of water under the ship. The received pulse is displayed on a chart by a pen recorder so that the navigator can see the outline of the bottom over which the vessel is passing. A similar device is the sonar system, which uses high frequency sound signals. In sonar the sound signal can be sent ahead or sideways. The time for the echo to be sent back from an object, such as an underwater rock, is a measure of the object’s distance from the ship. The sonar system can also be used to measure the speed of the ship over the seabed.
音频列表
- 2021-04
- 2021-04
- 2021-04
- 2021-03
- 2021-03
- 2021-03
- 2021-03
- 2021-03
- 2021-03
- 2021-03
查看更多
用户评论