宽带频率源的设计与实现

发布时间：2018-04-09 00:03

本文选题：频率合成器　切入点：锁相环　出处：《电子科技大学》2015年硕士论文

【摘要】：随着半导体技术的发展,频率合成技术也有了很大的进步,从最初的直接频率合成技术到间接频率合成技术再到最新的直接数字频率合成技术。技术的进步同样使得电子系统对频率合成器的指标有了越来越高的要求。作为电子系统的心脏,频率合成器性能的好坏会直接影响到整个系统的性能。本文提出了一种2.5GHz-14.6GHz超宽带低相位噪声频率合成器的实现方法。本文首先介绍了频率合成技术的发展历程,并介绍了每个发展阶段中重要的频率合成技术的特点以及频率合成器的关键指标,然后介绍了2.5GHz-14.6GHz超宽带频率合成器的需求指标,通过指标分析了实现此频率合成器需要用到的关键技术以及方法。通过分析,最终选定使用PLL+DDS的结构实现频率合成器,通过对锁相环系统的分析,将锁相环系统分解成鉴相器、预分频器、小数分频器、振荡器等几个部分,其中频率步进主要由小数分频器决定;杂散主要由鉴相器和小数分频器决定;各部分对相位噪声都有一定影响。通过对每部分的分析,对每一部分都给出了一两种可选方案。本文随后对分析中所提到的每部分的方案进行了设计与实现,在设计过程中对备选方案进行了最终的确认,同时对一些分析过程中没有注意到的以及不合理的地方进行了补充以及更正。同时给出了每个模块设计过程中需要注意的问题并给出了相应的解决方案。然后给出了每部分的原理图、PCB板图以及实物图。最后给出了屏蔽腔体的设计图。通过测试,文章设计的频率源频率步进小于1Hz,非谐波杂散抑制基本满足-75dBc的要求,输出功率满足10dBm的要求,全频段相位噪声优于-85dBc/Hz@10kHz。基本满足了设计指标的需求。文章最后对频率源存在的问题以及改进方法进行了简单阐述。
[Abstract]:With the development of semiconductor technology, frequency synthesis technology has made great progress, from the initial direct frequency synthesis technology to indirect frequency synthesis technology to the latest direct digital frequency synthesis technology.The progress of technology also makes the electronic system to the frequency synthesizer index has the higher and higher request.As the heart of electronic system, the performance of frequency synthesizer will directly affect the performance of the whole system.In this paper, a realization method of 2.5GHz-14.6GHz ultra-wideband low phase noise frequency synthesizer is presented.In this paper, the development of frequency synthesis technology is introduced, and the characteristics of frequency synthesizer and the key index of frequency synthesizer are introduced. Then the requirement index of 2.5GHz-14.6GHz UWB frequency synthesizer is introduced.The key techniques and methods used to realize the frequency synthesizer are analyzed.Through analysis, the structure of PLL DDS is selected to realize the frequency synthesizer. By analyzing the PLL system, the PLL system is decomposed into several parts, such as phase discriminator, predivider, fractional frequency divider, oscillator and so on.The frequency step is mainly determined by the fractional frequency divider, the spurious is mainly determined by the phase discriminator and the fractional frequency divider, and each part has certain influence on the phase noise.Through the analysis of each part, we give one or two alternative schemes for each part.Then, this paper designs and implements each part of the program mentioned in the analysis, and finally confirms the alternatives in the design process.At the same time, some unnoticed and unreasonable areas are supplemented and corrected.At the same time, the problems that should be paid attention to in the design of each module are given and the corresponding solutions are given.Then, the schematic diagram of each part and the physical diagram are given.Finally, the design diagram of the shielded cavity is given.The results show that the frequency step of the designed frequency source is less than 1Hz, the non-harmonic spurious suppression meets the requirement of -75dBc, the output power meets the requirement of 10dBm, and the phase noise in the whole frequency band is better than -85dBc / Hzr / Hz10kHz.Basically meet the requirements of the design indicators.At the end of the paper, the problems of frequency source and the improvement methods are briefly described.
【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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