Long-range Navigation Shortwave Receiver Rf Front-end Design And Implementation,

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.