| With the universal application of microelectronic technology to modern wars, microelectronic confrontation technology becomes the most important means to decide who will win the war, and the radio communication confrontation technology is the nucleus of commanding, controlling, communication and information confrontation system. Especially in the case of the regional wars that the United States army was involved in, it has aroused special attention from different governments and armies, who are willing to invest large amounts of money and human resources in conducting research on electronic confrontation technology, especially FHSS.FHSS is widely applied in military communication field because of its strong anti-interference, anti-jamming and anti-interception ability. As the RF front-end of FHSS, the development of the radio receiver tends towards high performance and high integration. Modern radio receiver is in pursuit of large dynamic range, good linearity, high sensitivity, better adaptability and strong anti-interference ability and so on. That extremely promotes the development of the receiver. Also these requirements also promoted the VHF frequency hopping radio receiver advances.This work was supported by the No.50 Research Institute of China Electronics Technology Group Corporation under Project the new generation of VHF frequency hopping radio project. The author was responsible for implementation radio receiver front-end. The receiver front-end requires that the receiver is to achieve high selectivity, large dynamic range, strong anti-interference, and excellent adaptability, using a two stage amplifier to improve profits. The driving amplifier is implemented by the power amplifier chip BLF404 produced by the NXP Company, and the end of the amplifier uses the power chip BLF245B from the NXP Company. Besides considering the linearity, we also need to try to improve work efficiency, so we choose the class AB, and adopt the push-pull structure to design the broadband, reasonably taking these two indicators--both the linearity and efficiency---into consideration. On the basis of this, the tube amplifier BLF245B is used with reducing voltage. On the premise of guaranteeing the linear indicators, it helps to greatly improve the work efficiency. Before the driving stage and after the last stage of power amplifier, the design uses the frequency hopping filter with fast frequency hopping and high inhibition degree. The filter adopts double tuned LC oscillation circuit, multiple sets of PIN diode switch and capacitor array unit to realize the function of the high precision variable capacitor. Through parallel resonance on different frequencies, it can realize the function of segmental filtering. Before the schematic and PCB design, the design applies ADS simulation software to realize the simulation optimization design of the power amplifier and the filter, thus theoretically proving the rationality of the design. Finally through debugging repeatedly, the design achieves the best performance.The paper begins with the introduction of the principle of frequency-hopping communication technologies, and describes the characteristics of frequency-hopping communication systems; followed by the deep analysis of the receiver’s structure, and then put forward the design proposal of the work, the key parameters and technical difficulties. Subsequently, the author analyzes key parameters of the receiver, presents the design proposal to achieve the targets and proof. Then the thesis elaborates on the specific circuit of the subject, implementation of each functional unit, including the high-frequency amplification unit and the IF amplification unit, namely, through their design to achieve large dynamic range and high selectivity. Then some questions in system design and debug are discussed in detail. Finally, the ultimate testing results of this subject are represented at last. |
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