Englishpresentation(手机).ppt
《Englishpresentation(手机).ppt》由会员分享,可在线阅读,更多相关《Englishpresentation(手机).ppt(13页珍藏版)》请在装配图网上搜索。
The development of mobile phone,Hui yang Feng zijian Zhao qingyuan,1.Concept ion,Mobile phone, commonly known as mobile phone, laptop, old mobile telephone terminal, can move in a large range of portable.,2.The origin of the phone,Day in April 1973, a man standing on the streets of New York, took out a wireless phone about two bricks, and hit a pass, attracted passers-by have stopped eyebrows. This person is the inventor of the mobile phone Martin Cooper. At that time, Cooper is a well-known American Motorolas engineering and technical personnel.,Martin Cooper,3.The division of the times,1) 1G,Only for voice communication, reception with instability, lack of confidentiality, the use of wireless bandwidth is not sufficient.,2)2G,These phones usually use PHS, GSM or CDMA are very mature, with a stable call quality and suitable standby time.,3) 3G,For third generation mobile communication systems (3G) mobile phone has been developed, but there is no universal related networks, has not been widely used. The beginning of the third generation mobile phone one of the goals is to develop a wireless communication system can be global, but the actual end result is that there are a variety of different formats, WCDMA, CDMA2000 and TD-SCDMA in the competition. These new formats are based on CDMA (Code Division Multiple Access) technology, further development in bandwidth utilization and data communications,4.The direction,The mobile phone of the future will be emphasis on security and data communications. The one hand, to strengthen the protection of personal privacy, on the other hand, strengthen the research and development of data services, more multimedia features are introduced in, the phone will have a more robust computing power, a personal information terminal, rather than just calls and text messages function.,concept machine,Thank you!,- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- Englishpresentation 手机
装配图网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
关于本文
相关资源
更多
相关搜索