快速切换频率综合器的设计与实现

发布时间：2018-06-05 16:19

本文选题：频率综合器 + 锁相环　；参考：《电子科技大学》2015年硕士论文

【摘要】：频率综合器在现代电子系统领域内应用广泛,被称为电子系统的心脏。随着科学技术水平的不断提升,对频率综合器的指标的要求也越来越高,其中频率切换时间作为重要的指标之一,逐渐成为研究的热点。YIG调谐振荡器(简称YTO),是以YIG铁氧体小球作为谐振源的微波振荡器。相比VCO(压控振荡器)其调谐带宽可以做到很宽,因为YIG振荡器具有很高的Q值,其相位噪声性能优异,由于其线性度好、调谐范围宽、供电简单等优点广泛应用于电子对抗、频谱分析仪、抗干扰接收机及微波仪器中做本地振荡器。由于YTO激磁线圈中电感的存在和振荡电路的涡流效应,使得YTO存在一定的磁滞效应,影响其快速的频率响应能力。如何减小其动态滞后效应从而提高调谐速度,是本文研究的重点。本文采用基于YTO为主振的频率合成方案,实现一款宽频带、低相噪的快速切换频率综合器。本文首先介绍了频率合成技术的基本原理,包括直接频率合成技术、锁相式频率合成技术、直接数字频率合成技术,并给出了频率切换时间的测量方法。经过方案对比,平衡系统指标的需求,最终采用了以YTO为振荡源的DDS激励PLL的混合式频率合成方案。针对YTO的动态滞后效应,通过分析YTO的电路模型,论述了其频率滞后特性中电流对电压、磁场对电流的滞后,分析了频率切换时即阶跃电压下YTO的输出响应方程,并以此给出加快频率响应的理论依据。采用了在频率切换过程中叠加调谐冲击电压的方案,克服YTO的动态滞后效应,使得频率输出快速进入捕获带并适时恢复正常预置值,实现频率的快速切换。本文给出了方案的具体实现,对关键电路模块给出了设计和仿真,通过FPGA实现对系统的程序控制,完成了系统的整体设计。最后通过调试,测试,给出了最终的测试结果,满足了系统的设计指标。
[Abstract]:Frequency synthesizer is widely used in the field of modern electronic system, which is called the heart of electronic system. With the continuous improvement of the level of science and technology, the demand for the index of frequency synthesizer is becoming higher and higher. Frequency switching time is one of the important indexes, and it has gradually become a hot.YIG tuned oscillator (YTO), which is YI G ferrite ball as the resonant source of the microwave oscillator. Compared with the VCO (voltage controlled oscillator), the tuning bandwidth can be very wide, because the YIG oscillator has a very high Q value, its phase noise performance is excellent, because of its good linearity, wide tuning range, simple power supply and so on, it is widely used in electronic countermeasures, spectrum analyzer, anti-jamming receiver. Because of the existence of inductors in the YTO magnetizing coil and the eddy current effect of the oscillating circuit, the YTO has a certain hysteresis effect, which affects its fast frequency response ability. How to reduce the dynamic hysteresis effect and improve the tuning speed is the key point of this paper. This paper adopts the main vibration based on YTO. In this paper, the basic principle of frequency synthesis technology, including direct frequency synthesis, phase-locked frequency synthesis and direct digital frequency synthesis, is introduced in this paper, and the method of measuring frequency switching time is given. In order to meet the requirement of the system index, the hybrid frequency synthesis scheme of DDS excited PLL with YTO as the oscillator is finally adopted. According to the dynamic hysteresis effect of YTO, by analyzing the circuit model of YTO, the hysteresis of the current to voltage and magnetic field to the current in the frequency hysteresis characteristics is discussed, and the output response of YTO under the step voltage is analyzed. The theoretical basis for accelerating the frequency response is given, and a scheme to overlay the tuning impact voltage in the process of frequency switching is adopted to overcome the dynamic hysteresis effect of YTO, make the frequency output quickly enter the capture band and restore the normal preset value at the right time, and realize the fast switching of the frequency. This paper gives the concrete realization of the scheme, and the key to the key. The circuit module gives the design and simulation, realizes the program control to the system through FPGA and completes the whole design of the system. Finally, the final test results are given through debugging and testing, and the design index of the system is satisfied.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN74

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