外文翻译---微波低噪声放大器分析
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1、 Microwave low noise amplifier analysis Microwave is the development of the wireless communication and development is not divided. 1901 years MaKeNi use 800 KHz medium-wave signals from Britain to the world of the north American Newfoundland first trans-atlantic radio communication test, a new era o
2、f human wireless communication. Wireless communication at the initial stage, people use long wave spread to communication. The 1920 s people discovered the shortwave communication, until the 1960 s, the rise of satellite communications, it has always been the main international long distance communi
3、cation means, and to the current emergency and military communication is still important. The waves of transmission for space is an electromagnetic 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
4、 we put to more than 300 MHz frequency electromagnetic wave called a microwave. Because each band spread characteristics of each different, can be used for different communication system. For example, the main wave travel along the ground, the diffraction ability strong, suitable for radio and sea c
5、ommunication. And short wave has strong the ionosphere reflection ability, it is fit to global communication. Ultrashort wave and microwave diffraction ability is bad, can be used as stadia or beyond visual range relay communication. Microwave communication is the product of the 20 th century 50 s.
6、Because of its large capacity and investment of communication cost province (accounts for about one 5 of the cable investment, high construction speed, combat ability of advantage and achieve rapid development. The 1940 s to the s produced transmission frequency band is wide, the performance is stab
7、le microwave communication, be long and large capacity wireless transmission lines to the ground of the main means, analog FM transmission capacity up to 2700 road, also can simultaneously transmit high quality color television, and then gradually entered the capacity and even in large capacity digi
8、tal microwave transmission. Since the mid 80 s, along with the frequency selective dispersion of digital microwave transmission interrupt the decline of the influence that and a series of adaptive decline against the technology and high state modulation and testing the development of technology, dig
9、ital microwave transmission produced a revolutionary change. Special should point out is the 80 s through the 90 s the set of high speed up more adaptive coding state demodulation technology and signal processing and the rapid development of the signal detection technology, to todays satellite commu
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