外文翻譯---微波低噪聲放大器分析-其他專(zhuān)業(yè)-全文預(yù)覽
【正文】 ow noise amplifier analysis Microwave is the development of the wireless munication and development is not divided. 1901 years MaKeNi use 800 KHz mediumwave signals from Britain to the world of the north American Newfoundland first transatlantic radio munication test, a new era of human wireless munication. Wireless munication at the initial stage, people use long wave spread to munication. The 1920 s people discovered the shortwave munication, until the 1960 s, the rise of satellite munications, it has always been the main international long distance munication means, and to the current emergency and military munication is still important. The waves of transmission for space is an electromagic wave propagation of the speed is equal to the speed of light. Radio waves can be in accordance with the frequency or wavelength classification and named we put to more than 300 MHz frequency electromagic wave called a microwave. Because each band spread characteristics of each different, can be used for different munication system. For example, the main wave travel along the ground, the diffraction ability strong, suitable for radio and sea munication. And short wave has strong the ionosphere reflection ability, it is fit to global munication. Ultrashort wave and microwave diffraction ability is bad, can be used as stadia or beyond visual range relay munication. Microwave munication is the product of the 20 th century 50 s. Because of its large capacity and investment of munication cost provin
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