远距离导航短波接收机射频前端的设计与实现

【作者】 邓江；

【导师】 张玉兴；

【作者基本信息】 电子科技大学 ， 电路与系统， 2006， 硕士

【摘要】 短波通信是指利用波长为10-100m(频率为3-30MHz)的电磁波进行无线电通信的。实际上,许多人也把中波的高频段(1.5-3MHz)归到短波波段去,所以现有的许多短波通信设备,其波段往往扩展到1.5-20MHz。短波通信多年来被广泛应用于政府,军事,外交,气象,商业等领域,用以传送语音,文字,图像,数据等信息,尤其在军事部门,它始终是军事指挥的重要手段之一。短波通信之所以能吸引用户用它传递信息,最基本的原因是由于进行远距离通信时,仅需要不大的发射功率和适中的设备费用,这一宝贵的优点,使得世界各国近年来加紧了短波通信的研究,出现了各种新型的短波通信系统。本项目来源于电子科技大学成都赛英科技有限公司与哈尔滨工程大学自动化学院的合作项目“远距离导航短波接收机”,笔者负责其中接收机射频部分的研制,该射频接收机包括一个射频前端和3个DDS频率合成器。系统采用了两次变频超外差式结构设计,第一中频为高中频。另外系统还包含了三级自动增益控制单元,其中一级AGC作为选项,实现了较大的动态范围,并且整机的线性度也得到了保证。本文先介绍了当代无线电导航的状况以及发展趋势和无线电的传播,然后对接收机射频前端的关键技术指标进行了深入分析,还介绍了系统在大动态范围,高线性实现的一些设计方法,之后详述了本项目采用的方案、具体功能指标的实现以及在设计与实现中应该注意的问题,最后给出系统的测试结果。更多还原

【Abstract】 Short wave is used for wireless communication which the wavelength is from 10m-100m. In fact, the high frequency part of medium wave usually belongs to short-wave band. So many short wave communication equipments’band was extended to 1.5-20MHz. Short-wave communication has been applied to the field of government, military affairs, diplomacy, weather, business and so on for many years. It used for transmittiing audio, words, video, data and other information. Especially in military affairs, it is the vital part in military operations. Short-wave communication is attractive because only little power and proper expenditure is needed when it is used for long distance communication. For this valuable trait, many country have expanded the area of short-wave communication’s research, thus there has become more and more new-model communication system.The subject comes from the cooperation project“long distance navigation short-wave receiver”between Chengdu Sine Science &Technology Ltd. and Automatization School of Harbin Engineering University. The auther was responsible for implementation of the RF receiver of the system. The RF receiver consists of a RF front end, 3 DDS synthesizer. The high-intermediate-frequency superheterodyne structure with twice conversions is used.Three cascaded AGC units applies in the receiver system, one of them is used as the choice, for realizing a high dynamic range while the linearity of the system is well guaranteed.The paper begins with the deep analysis of modern wireless navigation. Subsequently, the communication of wireless is introduced as well as the key points of receiver’s RF front end. Then, the design methods of receiver with high linearity and high dynamic range are recommended too. Also, the blue print of the receiver, the achievement of function guide line and the problems in real debugging are discussed in detail. The ultimate testing results of this subject are represented at last.更多还原