雷达目标模拟器宽带小步进频综的研究与设计

发布时间：2018-04-03 17:09

本文选题：频率合成　切入点：DDS　出处：《南京航空航天大学》2015年硕士论文

【摘要】：雷达目标模拟器因其能够克服外场试验成本高、周期长且回波参数难以控制的缺点而得到广泛研究与应用。随着现代雷达系统日趋复杂,功能更加完备,对目标模拟器的频率合成器提出了越来越高的要求。结合具体项目需要,本文针对5GHz~9GHz宽带、小步进、低相噪、低杂散微波频率合成器进行了论证实现。本文主要工作如下:(1)讨论了直接频率合成(DS)、锁相环频率合成(PLL)、直接数字频率合成(DDS)以及混合频率合成这几种主流频率合成技术的基本原理和优缺点,结合本课题捷变频的要求,最终确定系统方案为DDS+PLL环外混频的频率合成方式。(2)根据系统方案,采用AD9912芯片,设计了DDS电路,输出频率范围150~400MHz,最小频率步进250Hz,输出功率3dBm,相位噪声典型值为-116dBc/Hz@10KHz。(3)根据系统方案,采用ADF4350和ADF4107等芯片,设计了多个PLL电路,输出频率分别为1.4/3/4/5/6GHz,输出功率可达10dBm,杂散抑制典型值为60d Bc。(4)利用多级放大器、倍频器、混频器和滤波器设计了上变频链路,实现了5~9GHz输出、1KHz步进的宽带频率合成器。输出功率为0dBm,相位噪声典型值为-90dBc/Hz@10KHz,杂散抑制典型值为50dBc。
[Abstract]:Radar target simulator has been widely studied and applied because it can overcome the disadvantages of high cost, long period and difficult control of echo parameters.With the complexity of the modern radar system and the more complete function, the frequency synthesizer of the target simulator is required more and more.In this paper, 5GHz~9GHz broadband, small step, low phase noise, low spurious microwave frequency synthesizer is demonstrated and implemented.The main work of this paper is as follows: (1) the basic principles, advantages and disadvantages of direct frequency synthesis (DSN), phase-locked loop frequency synthesis (PLL), direct digital frequency synthesis (DDS) and hybrid frequency synthesis are discussed.The final scheme of the system is the frequency synthesis method of DDS PLL external mixing. According to the system scheme, the DDS circuit is designed by using AD9912 chip.The output frequency range is 150 ~ 400 MHz, the minimum frequency step is 250 Hz, the output power is 3dBm, and the typical phase noise is -116dBc / Hz @ 10KHz. 3) according to the system scheme, several PLL circuits are designed by using ADF4350 and ADF4107 chips.The output frequency is 1.4 / 3 / 4 / 5 / 6 GHz, the output power is up to 10 dBm, and the typical spurious suppression value is 60 dB c. 4) by using multistage amplifiers, frequency multipliers, mixers and filters, an up-conversion link is designed to realize the 5~9GHz output 1kHz step broadband frequency synthesizer.The output power is 0 dBm, the typical phase noise is -90 dBc / Hz @ 10kHz, and the spurious suppression is 50 dBc.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN955;TN74

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