Origin最低版本: 8.1SR0 1. 导入Origin安装目录下的文件 \Samples\Signal Processing\Sine Signal with High Frequency Noise.dat. 2. 选中Worksheet中两列, 菜单选择 Plot: Line: Line 作一直线图 3. 菜单选择 Analysis: Signal Processing: Envelope 出现X-Function对话框. 4 . 在 Envelope type 下拉菜单中选择 Both Envelopes . 设置 Smooth Points 为1. 5. 按 OK 执行. 图形会出现上下的包络线. 可得到如下结果
In popular language, ocean and sea are used interchangeably. Today's seas are the North and South Pacific, North and South Atlantic, Indian and Arctic Oceans and the Antarctic waters or seas. Scientists believe that the seas are as much as 500 million years old because animals that lived then occur as fossils in rocks which once were under ancient seas. There are several theories about the origin of the seas, but no single theory explains all aspects of this puzzle. Many earth scientists agree with the hypothesis that both the atmosphere and the oceans have accumulated gradually through geologic time from some process of degassing of the Earth's interior. According to this theory, the ocean had its origin from the prolonged escape of water vapor and other gases from the molten igneous rocks of the Earth to the clouds surrounding the cooling Earth. After the Earth's surface had cooled to a temperature below the boiling point of water, rain began to fall and continued to fall for centuries. As the water drained into the great hollows in the Earth's surface, the primeval ocean came into existence. The forces of gravity prevented the water from leaving the planet. Source: http://www.palomar.edu/oceanography/salty_ocean.htm