应用于全数字锁相环的3.44～5.25GHz,FOM值为182dBc/Hz的低功耗数控振荡器设计

设计了一个应用于全数字锁相环的宽带电感电容数控振荡器(DCO).通过设计粗调谐电容阵列、中等调谐电容阵列和精细调谐电容阵列,实现了宽的调谐范围.采用NMOS和PMOS互补型交叉耦合电路,实现了低功耗、高优值(FOM)的振荡器.设计采用TSMC 0.13μm CMOS工艺,电源电压为1.2V.测试结果表明,DCO的调谐范围达到3.44～5.25GHz,调谐百分比为41.7%.在4.06GHz频率处,振荡器电路在1MHz频偏处的相位噪声为-117.6 dBc/Hz.在调谐范围内,设计的DCO电路在1 MHz频偏处的FOM值为182～185.5dBc/Hz.功耗为1.44～3.6mW.     

基于最小变电容结构的数控LC振荡器

提出了一种数控最小变电容结构,采用互补型变容管两端跨接固定电容结构,可以使用较大尺寸变容管实现较小的最小变容值,从而减小了工艺误差对设计结果的影响,同时解决了大摆幅振荡信号下的非线性问题,缓解失配电容对失配率一致性对最小变容值的影响.在相同工艺下,最小变电容值减小接近50%.采用180nm CMOS工艺,基于最小变电容结构设计了全数控LC振荡器,通过改变各级数控变电容阵列的结构,提高全数控LC振荡器的频率分辨率.仿真结果表明:提出的最小变电容结构可实现7.42aF的最小变电容值;全数控LC振荡器的振荡频率范围为3.2~3.8GHz,输出电压摆幅为1.75V,中心谐振频率3.5GHz的相位噪声为-1.2×10-4 dBc/Hz,归一化价值因子FOM为211;在相位噪声、功耗、FOM等性能指标维持在同等水平的前提下,调频精度显著提高.     

GPS/BD 接收机中电感电容压控振荡器设计

采用TSMC 0.18 μm CMOS工艺,设计了一款宽调谐、低相位噪声、低功耗的电感电容压控振荡器(voltage controlled oscillar,VCO),用于接收北斗卫星导航系统的B1,B2频段信号和全球定位系统(global positioning system,GPS)的L1频段信号的射频接收机中.振荡器中采用了开关固定电容阵列和开关MOS管可变电容阵列,有效地解决了宽频率调谐范围和低相位噪声之间不可兼顾的问题,另外,采用了可变尾电流源的结构,使得振荡器在整个可调频率范围内输出电压的幅度变化不大.利用Cadence软件中Spectre对电路进行仿真.结果表明,振荡器频率调谐在2.958-3.418 GHz和2.318-2.552 GHz这2个频段内,在1.8V的供电电源电压下,功耗仅为3.06-3.78mW.当振荡器工作在3.2 GHz和2.4 GHz的中心频率时,其在1 MHz频偏处的单边相位噪声分别为-118 dBc/Hz和-121 dBc/Hz.     

频率分辨率改进型数控振荡器的设计

设计了一个应用于四频带全球移动通信系统(GSM)收发机的频率分辨率改进型数控振荡器.提出了一种新型串联开关变容管模型并进行理论分析,将其应用在振荡器的精确调谐电容阵列中,验证了其对频率分辨率增强的性能.设计采用90 nm互补金属氧化物半导体工艺,当谐振在3.1 GHz时,数字加抖前的频率分辨率达到1.6 kHz,距中心频率20 MHz处的相位噪声为-152 dBc/Hz,功耗8.16 mW.仿真表明,该频率分辨率改进型数控振荡器满足四频带GSM收发机的要求,适于应用在全数字锁相环中.     

应用于IMT-A和UWB系统的双频段开关电流源压控振荡器设计

采用TSMC 0.13μm CMOS工艺设计了一款宽带电感电容压控振荡器(LC-VCO).LC-VCO采用互补型负阻结构,输出信号对称性较好,可以获得更好的相位噪声性能.为达到宽的调谐范围,核心电路采用4 bit可重构的开关电容调谐阵列以降低调谐电路增益,并使用可变电容在每段开关电容子频带上实现调谐.此外,压控振荡器的设计采用了开关电流源、开关交叉耦合对和噪声滤波等技术,以优化电路的相位噪声、功耗、振荡幅度等性能.整个芯片(包括焊盘)面积为1.11 mm×0.98 mm.测试结果表明,在1.2 V电源电压下,UWB和IMT-A频段上压控振荡器所消耗的电流分别为3.0和5.6 mA,压控振荡器的调谐范围为3.86～5.28和3.14～3.88GHz.在振荡频率3.534和4.155 GHz上,1 MHz频偏处,压控振荡器的相位噪声分别为-122和-119 dBc/Hz.     

电感及电容结构的压控振荡器电路设计与仿真

随着通信技术对射频收发机性能要求的不断提高,高性能压控振荡器已成为模拟集成电路设计、生产和实现的关键环节。针对压控振荡器设计过程中存在相位噪声这一核心问题,文中采用STMC 0.18μm CMOS工艺,提出了一种1.115 G的电感电容压控振荡器电路设计方案,利用Cadence中的Spectre RF对电路进行仿真。研究结果表明:在4～6 V的电压调节范围内,压控振荡器的输出频率范围为1.114 69～1.115 38 GHz,振荡频率为1.115 GHz时,在偏离中心频率10kHz处,100 kHz处以及1 MHz处的相位噪声分别为-90.9 dBc/Hz,-118.6 dBc/Hz,-141.3dBc/Hz,以较窄的频率调节范围换取较好的相位噪声抑制,从而提高了压控振荡器的噪声性能。     

正交输出、双调谐、高性能4.488GHz环形振荡器设计

设计了一个4级延迟单元的环形振荡器,通过采用2条辅助通路结构,实现了振荡器的双调谐功能和高的FOM(figure of merit)值.设计采用Jazz 0.18μm CMOS工艺,在1.6 V电源电压下的电流消耗为18.98mA.后仿真结果显示,VCO输出中心频率和增益分别为4.488 GHz和147 MHz/V,频率粗调谐范围为1.42GHz.频偏1 MHz处的相位噪声为-104.3 dBc/Hz.在频偏1 MHz和5 MHz处FOM值分别为169.1和173.39.     

一个1.5V低相位噪声的高频率LC压控振荡器的设计

介绍了一种适用于DCC-1800系统的压控振荡器的设计,中心频率为3．6GHz．分析并比较了三种降低相位噪声的方法并进行了仿真验证,然后阐述了3．6GHz压控振荡器器件尺寸的优化分析．采用电感电容滤波技术降低相位噪声,在偏离中心频率600kHz处,仿真得到相位噪声为-117dBc／Hz,调谐范围达到26．7％．VCO电路在1．5V电压下工作,静态电流为6mA．     

1.8 GHz～2.4 GHz的宽带压控振荡器设计

利用微波晶体管的负阻特性,设计出可调范围为1.77 GHz-2.52 GHz的宽带可调压控振荡器（VCO）.通过引入高频衰减电路,改善了VCO在其频带内输出功率的平坦性,并用Ansoft Designer SV软件仿真了VCO的特性.结果表明,带内输出功率稳定在9.96 dBm-10.08 dBm,相位噪声在1.8 GHz和2.4 GHz分别为-113.3 dBc/Hz/600 kHz、-114.9 dBc/Hz/600 kHz.     

一种宽调谐范围的毫米波LC压控振荡器设计

基于TSMC 65 nm CMOS工艺,设计了一种具有宽调谐范围的毫米波电感电容压控振荡器,振荡器采用开关电容阵列、大容值范围可调电容和大滤波电容实现频率调谐范围与相位噪声的双优化.通过三组开关电容阵列来获得八条子频段,优选容值范围较大的可调电容来细调每一个频段的振荡频率,获得较大的调谐增益Kvco,从而最大程度地提高频率调谐范围.通过大滤波电容与尾电流源构成的低通滤波器抑制偶次谐波附近的噪声,从而优化相位噪声.仿真结果表明,在1. 2 V的工作电源电压下,压控振荡器的频率调谐范围22. 2 G～29. 2 GHz,中心频率25. 7 GHz,在1 MHz频率偏移处的相位噪声-100. 9 dBc·Hz~(-1),功耗10. 81 mW,芯片核心面积为0. 056 mm~2.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the