基于CMOS工艺的电感电容振荡器相位噪声和电流效率研究

发布时间：2018-04-15 21:05

本文选题：B类 + C类　；参考：《中国科学技术大学》2015年硕士论文

【摘要】：振荡器作为无线通信系统中的最重要的模块之一,担负着频率产生和时钟参考的重要任务。在集成射频收发系统中,振荡器的相位噪声会直接影响到接收机的噪声系数和发射机的误差向量幅度。因此,数十年来,振荡器的相位噪声始终是射频集成电路方向的研究热点。近年来,随着手持移动设备的普及,低功耗电路设计的需求逐年增加。由于振荡器是射频收发系统中的一个高功耗模块,如何实现一个低功耗且低噪声的振荡器成为了研究热点,这推动了振荡器能量效率研究的浪潮。在这其中,振荡器的电流效率,因其和振荡器输出幅度、相位噪声的密切关系,成为一个尤为令人关注的话题。 CMOS电感电容振荡器因其在较低功耗下可呈现低相位噪声的优势在通信系统中广泛应用。本文重点研究了电感电容振荡器的相位噪声和电流效率。尤其针对在学术界和工业界使用最广泛的传统B类振荡器,本文给出了精确的电流效率模型和范围。研究结果表明,在综合性能指标FoM的优化点处,传统B类振荡器的电流效率范围在0.60至0.85之间。这修正了广为使用的假设——电流效率在所有B类振荡器中为2／π。此外,论文将理论拓展到交流耦合的B类振荡器和C类振荡器。分析显示,两种B类振荡器的电流效率相同,C类振荡器的电流效率在0.85和1之间。论文还详细讨论了电感电容振荡器的相位噪声行为,并将两种线性相位噪声模型与振荡方程联系起来,揭示了其背后的机理。利用线性时变模型的脉冲敏感函数,本文给出了适用于小幅度和大幅度的B类振荡器相位噪声模型。并结合电流效率的分析结果,给出了修正后的FoM的闭环表达式。此外,利用上述分析结果,论文还讨论了一些振荡器设计中的关键技术和概念,这包括电感电容振荡器中尾电容的作用,电压受限区和电流受限区的划分以及B类振荡器和C类振荡器的效率比较等。分析显示,B类和C类振荡器的的主要性能区别在于电压效率而非电流效率。论文还介绍了当前国际上流行的电感电容数控振荡器的一些基本概念,并总结了当前的先进国际研究成果。最后,文中提出了一个基于脱敏尾电容的高分辨率电感电容数控振荡器的新颖的调谐方式。论文给出了尾电容和输出频率之间的敏感度的量化分析,并对尾电容对于相位噪声的影响给出了定性分析。分析和仿真结果显示,如果尾电容设计得当,数控振荡器的相位噪声和分辨率可被同时提高。
[Abstract]:As one of the most important modules in wireless communication system, oscillator is responsible for frequency generation and clock reference.In the integrated RF transceiver system, the phase noise of the oscillator will directly affect the receiver noise coefficient and the error vector amplitude of the transmitter.Therefore, the phase noise of the oscillator has always been the research hotspot of RF integrated circuit for decades.In recent years, with the popularity of handheld mobile devices, the demand for low power circuit design increases year by year.Because the oscillator is a high-power module in RF transceiver system, how to realize a low-power and low-noise oscillator becomes a research hotspot, which promotes the research of oscillator energy efficiency.Among them, the current efficiency of the oscillator, because of its close relationship with the output amplitude and phase noise of the oscillator, has become a topic of particular concern.CMOS inductively capacitive oscillator is widely used in communication systems because of its advantage of low power consumption and low phase noise.In this paper, the phase noise and current efficiency of inductively capacitive oscillator are studied.Especially for traditional B type oscillators, which are widely used in academia and industry, this paper presents an accurate current efficiency model and range.The results show that the current efficiency ranges from 0.60 to 0.85 at the optimization point of the comprehensive performance index FoM.This modifies the widely used assumption that current efficiency is 2 / 蟺 in all class B oscillators.In addition, the theory is extended to class B oscillator and class C oscillator.The analysis shows that the current efficiency of the two type B oscillators is the same as that of the C type oscillators. The current efficiency of the two type B oscillators is between 0.85 and 1.The phase noise behavior of inductively capacitive oscillator is discussed in detail, and the two linear phase noise models are connected with the oscillation equation to reveal the mechanism behind it.Based on the pulse sensitivity function of the linear time-varying model, a phase noise model for small amplitude and large amplitude B oscillators is presented in this paper.Combined with the analysis results of current efficiency, the closed-loop expression of modified FoM is given.In addition, based on the above analysis results, some key techniques and concepts in oscillator design are discussed, including the role of tail capacitance in inductance capacitor oscillator.The division of voltage limited region and current-limited region and the comparison of efficiency between class B oscillator and class C oscillator.The analysis shows that the main difference between class B oscillator and class C oscillator lies in voltage efficiency rather than current efficiency.This paper also introduces some basic concepts of inductance capacitor numerically controlled oscillator which is popular all over the world, and summarizes the current advanced international research results.Finally, a novel tuning method of high resolution digital controlled inductance capacitor oscillator based on desensitized tail capacitor is proposed.A quantitative analysis of the sensitivity between the tail capacitance and the output frequency is given, and the effect of the tail capacitance on the phase noise is analyzed qualitatively.The results of analysis and simulation show that the phase noise and resolution of the numerical controlled oscillator can be improved simultaneously if the tail capacitance is properly designed.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN752

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