.350 Mhz, Band Miniaturized Fm Receiver,

UHF radio station possesses extensive military applications as well as civil, being of great value in research and development. The subject comes from the cooperation project"special FM receiver module"between the Sine Science Technologies Co., Ltd. of Chengdu. and the Kehong Electronic Device Factory of Chengdu. The author was responsible for implementation the whole receiver of the system. The superheterodyne structure with twice conversion is adopted to the receiver which is consisted of a RF front end, a PLL frequency synthesizer of which the VCO is designed by the author and an audio amplifier module, and it is also provided with the characteristic including pint-sized, low power supply and low cost. The paper begins with the analysis of receiver parameters, the propogation and modeling of mobile radio, and the theory of designing PLL frequency synthesizer and VCO. Then, the system scheme analysis and proof, implementation of each functional unit, and some questions needed paying more attention in system design and debug are discussed in detail. The ultimate testing results of this subject are represented at last.