CDMA2000系统微型直放站发信通道设计毕业论文.doc

CDMA2000系统微型直放站发信通道设计
摘要
直放站是随着移动通信的发展而出现的一种无线通信设备。直放站的应用在第一代模拟移动通信网建立时就已经开始,随着移动通信技术向纵深发展,通信网络面临着一个如何提高网络覆盖质量的问题。直放站以低投入、低成本、相对短的建设周期和较好的网络质量提高了网络信号的覆盖率,已经成为无线网络覆盖中的重要设备。
目前,第三代移动通信技术已成为国内外移动通信领域的研究热点,相应的射频技术也是通信领域的主要研究方向。本文首先总结3G的系统,特点及三种无线传输方案,然后介绍了CDMA2000的工作原理和体系结构,并对各种结构的相关概念、主要特点、关键技术进行了简要说明,此外,还简单介绍了无线通信信道的基本原理及传播损耗模型。接着介绍了移动通信直放站的原理和CDMA直放站的技术指标。最后从项目所要求的增益、噪声等指标入手,详述本课题硬件方案,作可行性论证,选取合适的芯片与电路结构实现了CDMA直放站的射频发射单元,并总结设计中注意的问题。
关键词:CDMA直放站;射频;硬件电路设计;低噪声放大器;功率放大器
Abstract
Along with the development of the munication, repeater is a munication equipment. When the 1st generation Analog work is established, the application of repeater had started,and as the munication technology has developed deeply, work meets a question ,that is how to improve the quality which work covers with. Repeater advances the coverage work signal with low devotion, low cost,relative short building cycle and work quality, and it has been an important equipment to work coverage.
At present, in the field of munication, the 3rd generation munication technology(3G) has e the research hotspot, and the relevant radio frequency technology is also the main investigative direction. In this paper, it summarizes the system structure and features of 3G and three primary kinds of radio transmission technology including CDMA2000 firstly, and then introduces the work principle and system structure of CDMA2000 detailedly and concretely, and it briefly explains the correlative conception, primary feature, and key technology. Besides, it also briefly introduces the basic principle and some transmission ullage models of munication. Where after , it introduces the principles of repeater used in munication and technology indexes of CDMA Repeater. Finally ,it proceeds with the indexes of gain, noise, etc, which required by the item, to discuss the hardware scheme in detail, to make feasible argumentation, and to choose the suitable chip and circuit structure. The radio repeater cell of selected frequency