Ka波段频率合成器技术研究

发布时间：2018-02-24 01:34

本文关键词： 频率综合器 Ka波段 DDS PLL 相位噪声杂散抑制捷变频　出处：《电子科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：频率源是雷达、通信等电子系统的心脏,并且在制导、射电天文学、临床医学等领域也有重要意义,其性能的好坏直接影响各电子系统的指标[1]。本文对Ka波段的频率合成技术进行了杂散、相噪、变频速度、体积等方面的研究,研制出了综合性能优异的频率合成源。首先,本文对频率合成技术基本理论进行了阐述,分析了各种技术的优劣,结合文章的指标要求,并进行指标初步核算之后,确定了以DDS驱动PLL为框架结构的方案。然后,在DDS驱动PLL的基本框架之上,对方案进行具体的设计。最终信号要求为Ka波段,为了降低设计难度,先实现X波段的信号输出,再经过3倍频实现最终的Ka频段输出。为了解决低相噪的要求,采用VCO输出先下变频再分频的方法,使得反馈回路的分频比大大减小,从而有效降低相噪。为了达到输出低杂散的要求,应尽量减小DDS的输出频率及带宽。本文先采用固定本振,分频比N可变的方法来实现,测试发现某些频点不能锁定;然后改用固定分频比N,本振切换的方法来实现。最终发现后者可以解决前者在某些频点不能锁定的情况。最后,将系统级联测试,得到最终的测试结果为:输出频率为34~36GHz;相位噪声优于-90dBc/Hz@1KHz;杂散优于-60dBc;频率分辨率优于53Hz;跳频时间优于7微秒(33.9GHz跳至36GHz),均满足指标要求。
[Abstract]:Frequency sources are the heart of electronic systems such as radar, communications, and are also of great significance in the fields of guidance, radio astronomy, clinical medicine, etc. The performance of Ka-band frequency synthesis technology is studied in the aspects of spurious, phase noise, frequency conversion speed, volume and so on, and a frequency synthesizer with excellent comprehensive performance is developed. In this paper, the basic theory of frequency synthesis technology is expounded, and the advantages and disadvantages of various techniques are analyzed. Combined with the index requirements of the article, and after preliminary accounting of the indicators, the scheme of using DDS driven PLL as the frame structure is determined. Based on the basic frame of DDS driving PLL, the scheme is designed concretely. The final signal is Ka-band. In order to reduce the design difficulty, the X-band signal output is realized first. In order to solve the problem of low phase noise, the method of VCO output first down conversion and then frequency division is adopted, which reduces the frequency division ratio of feedback loop greatly. In order to achieve the requirement of low spurious output, the output frequency and bandwidth of DDS should be reduced as far as possible. Finally, it is found that the latter can solve the situation that the former can not be locked at some frequency points. Finally, the system is cascaded to test. The final test results are as follows: the output frequency is 346GHz; the phase noise is better than -90dBc / Hzr @ 1kHz; the spurious is better than -60dBc; the frequency resolution is better than 53Hz; and the frequency hopping time is better than 7msec 33.9 GHz to 36GHz.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN74

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