文档介绍：Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 卫星通信卫星通信是利用人造地球卫星作为中继站。卫星把地面站送来的信号接收下来,进行放大,然后转发给另外的地面站。 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 通信卫星大多相对地球“静止”──同步卫星 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 三颗同步卫星可以基本实现全球通信 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 用碟形天线接收来自卫星的信号 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 中国北斗卫星导航系统 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. ?光导纤维简称光纤。?光纤是传输光信号的介质。?光纤通信中用的是激光, 而不是普通的光。因为普通光源发出的光中夹杂了许多频率的光,不但难以加载信息,而且通信质量差。激光亮度高, 单色性好,方向性好,能量始终集中在传播方向上,容易调制信号。光缆通信光缆通信 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 光是比微波频率高得多的电磁波。 光通信的“高速公路”更宽广。 利用频率单一、方向高度集中的激光进行通信,效果很好。 Evaluation only. Evaluation only. Created with Aspo