VHF跳频电台发射机射频前端研究及实现

发布时间：2018-03-28 16:48

本文选题：跳频通信　切入点：射频前端　出处：《复旦大学》2014年硕士论文

【摘要】：随着电子技术在现代战争的广泛应用,电子对抗技术成为战争胜利的最重要作战手段,而通信对抗是指挥、控制、通信和情报对抗系统中的核心部分。特别是美军在几次局部战争中的使用案例,已经引起各国政府和军方的高度重视,不惜投入大量的人力、物力,研究电子对抗技术,特别是跳频通信技术。跳频通信技术由于其优越的抗干扰、抗衰落、抗截获的能力,在军事通信领域被广泛应用。作为跳频通信的发射末级,无线电发射机在设计和实现上越来越趋向于高性能、高集成度方向。对于发射机的带宽,功率,线性度,效率,平坦度、抗干扰能力等方面的性能和指标也提出了越来越高的要求。这些需求也促进了VHF跳频电台发射机的不断进步,使得发射信号质量更好,发射距离的更远,抗干扰能力更强。课题来自于中国电子科技集团公司第五十研究所某新型VHF超短波跳频电台项目,是其中发射机射频前端的研制。该发射机射频前端要求射频功放具有宽频带,大功率,高线性度,高效率,平坦度好等特点,采用两级放大来达到增益的要求。推动级放大器选用了NXP公司的功放芯片BLF404来实现；末级选择了NXP公司的功放芯片BLF245B,除了考虑线性度,兼顾提高工作效率,所以选择AB类,采用推挽式结构进行宽带设计,合理的兼顾了线性度和效率这两个指标。在此基础上,对功放管BLF245B进行降压使用,在保证线性指标的前提下,大大提高了工作效率。在推动级之前和末级功放之后,采用了跳频速度快,抑制度好的跳频滤波器,该滤波器采用双调谐LC振荡回路,多组PIN二极管开关与电容阵列单元并联来实现高精度可变电容的功能,使之谐振于不同的频率上,实现分段滤波的功能。本设计在原理图和PCB设计之前,利用ADS仿真软件,对功放和滤波器进行仿真优化设计,理论上验证了设计方案的合理性。最终通过反复的调试,达到了最佳的性能。本文首先介绍了跳频通信技术的原理,讲述了跳频通信系统的特点；其次对功率放大器的几种结构形式进行了对比分析,提出了课题的设计方案、关键技术指标以及技术难点。然后分析了发射机的关键指标,提出并论证了实现各指标的设计方案。详述了本课题具体电路的设计与实现,包括功放单元和跳频滤波器单元两个主要模块的设计,最后进行电路调试,给出系统的测试结果。
[Abstract]:With the wide application of electronic technology in modern warfare, electronic countermeasure technology has become the most important means of war victory, and communication countermeasure is command and control. The core parts of the communications and intelligence countermeasures system, especially the cases of US military use in several local wars, have attracted great attention from governments and the military of various countries, and have spared no effort and resources to study electronic countermeasures technology. Especially frequency hopping communication technology. Frequency hopping communication technology is widely used in the field of military communication because of its superior ability of anti-jamming, anti-fading and anti-interception. The design and implementation of radio transmitters tend to be more and more high performance, high integration direction. For the transmitter bandwidth, power, linearity, efficiency, flatness, The performance and index of anti-jamming ability also put forward higher and higher requirements. These requirements also promote the continuous progress of VHF frequency hopping radio transmitter and make the quality of transmitting signal better and the distance of transmission more distant. The subject comes from the project of a new VHF ultra-short wave frequency hopping radio station in the 50th Research Institute of China Electronic Science and Technology Corporation, which is the development of the RF front-end of the transmitter. The RF front-end of the transmitter requires a wide band of RF power amplifier. High power, high linearity, high efficiency, good flatness and so on, the two-stage amplifier is adopted to achieve the gain requirement. The NXP power amplifier chip BLF404 is used to realize the push stage amplifier. In the final stage, NXP power amplifier chip BLF245B is selected. Besides considering linearity and improving working efficiency, AB class is chosen for broadband design with push-pull structure. The linearity and efficiency are reasonably taken into account. The power amplifier tube BLF245B is used to reduce the voltage, and the working efficiency is greatly improved under the premise of guaranteeing the linear index. Before the push stage and after the last stage power amplifier, the frequency hopping filter with high frequency hopping speed and good suppression degree is adopted. The filter uses double tuning LC oscillatory loop, multiple PIN diode switches and capacitor array units are connected in parallel to realize the function of high precision variable capacitance, which resonates at different frequencies. Before the schematic diagram and PCB design, the power amplifier and filter are simulated and optimized by using ADS simulation software. The rationality of the design scheme is verified theoretically. This paper first introduces the principle of frequency hopping communication technology, describes the characteristics of frequency hopping communication system, then compares and analyzes several structure forms of power amplifier, and puts forward the design scheme of the subject. The key technical specifications and technical difficulties are analyzed, and then the key indicators of the transmitter are analyzed, and the design scheme to realize each index is proposed and demonstrated. The design and implementation of the specific circuit of this subject are described in detail. It includes two main modules: power amplifier unit and frequency hopping filter unit. Finally, the circuit is debugged and the test results are given.
【学位授予单位】：复旦大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN914.41

【参考文献】