250 MHz 时钟产生电路中低抖动锁相环的仿真与设计

提出了一种基于行为级的锁相环(PLL)抖动仿真方法.分析了压控振荡器的相位噪声、电源和地噪声以及控制线纹波对输出抖动的影响.采用全摆幅的差分环路振荡器、全反馈的缓冲器以及将环路滤波器的交流地连接到电源端等措施,减小了PLL的输出抖动.给出了一个采用1st silicon 0.25μm标准CMOS工艺设计的250 MHz时钟产生电路中低抖动锁相环的实例.在开关电源和电池供电2种情况下,10分频输出(25 MHz)的绝对抖动峰峰值分别为358 ps和250 ps.测试结果表明该行为级仿真方法可以较好地对PLL的输出抖动做出评估.     

低耗能流水线模数转换器的运算放大器设计与仿真

基于0.13,μm工艺,设计一个用于1.2,V低电压电源的10比特83MSPS流水线模数转换器的两级运算放大器.该放大器采用折叠共源共栅为第一级输入级结构,共源为第二级输出结构.详细介绍了运算放大器的设计思路、指标确定方法及调试中遇到的问题和解决方法.模拟结果显示:该运算放大器开环直流增益可达79.25,dB,在负载电容为2,pF时的单位增益频率达到838 MHz,在1.2,V低电压下输出摆幅满足设计要求,高达1 V,满足了10比特低电压高速度高精度模数转换器的要求.     

高抗电源噪声的低时钟抖动VCO设计

设计了一种基于电流舵逻辑(CSL)架构的环型压控振荡器(VCO),对传统的共源共栅结构偏置电路作了进一步的改善,增加了一个电压增益较大的放大器构成有源负反馈,以提高抗电源噪声的能力.采用和舰0.18μm双阱CMOS工艺对传统结构VCO和改进后的VCO进行对比仿真,在频率为20MHz、峰-峰值为200mV的高频电源噪声下,传统结构VCO的峰-峰抖动和均方根抖动分别为54.135ps和19.454ps,而改进结构VCO的相应值分别为27.442ps和9.196ps,抗抖动性能大大提高.改进结构VCO的输出频率为650MHz,占空比约为52%,中心控制电压0.9V对应的增益为962.16MHz/V,线性度良好,在1.8V的直流电源下功耗仅为0.7mW左右.     

高速SerDes电路中电荷泵锁相环的设计

面向高速串行接口应用,设计一款低噪声、快速锁定的高性能锁相环电路,作为5 Gbit· s-1数据率的SerDes发射芯片的时钟源。该设计通过锁存RESET方式增加延迟时间,以减小鉴频鉴相器的死区效应,降低锁相环整体电路的杂散;其压控振荡器采用4 bit二进制开关电容的方法,将输出频率划分为16个子频带,以获得较大的输出频率范围,同时又不增加压控振荡器的增益;在SMIC 55 nm工艺下完成锁相环电路版图设计,核心芯片面积为054 mm2。后仿真结果表明:输出频率覆盖46~56 GHz,1 MHz频偏处的相位噪声在-110 dBc·Hz-1 附近。测试结果显示,RMS 抖动和峰峰值抖动分别为287 ps和134 ps,整体电路功耗为37 mW。     

宽带ADC低抖动时钟驱动电路的分析与设计

提出采用小信号模型对时钟驱动电路中由热噪声引起的时钟抖动进行分析,并提出采用多级准无穷负载差分放大器结构以有效地实现低抖动.通过Cadence Spectre RF的瞬态噪声仿真,可以得到时钟抖动值,在输入频率变化时将仿真结果与手工推导的结果相比较,推导的公式能较好地预测时钟驱动电路的时钟抖动.设计的时钟驱动电路达到了输入频率100 MHz、幅度为480 mV下时钟抖动仅为193 fs,可以应用于高性能模数转换器.     

可用于快速稳定PLL的低时钟抖动VCO设计

设计了一种基于电流控制逻辑（CSL）架构的650MHz环型压控振荡器(VCO),对传统的共源共栅结构偏置电路作了进一步的改善,加了一个电压增益较大的放大器构成有源负反馈以提高抗电源噪声的能力.同时也提出了一种阻尼因子控制电路结构,使该VCO可用于快速稳定的锁相环(PLL).该VCO采用和舰0.18μm双阱CMOS工艺仿真,在频率为20MHz、峰—峰值为200mV的高频电源噪声下,其峰-峰抖动和RMS抖动分别为22.649ps和7.793ps。该VCO输出频率为650MHz,占空比约为52%,增益(Kvco)为925.88MHz/V,线性度良好,在1.8V的直流电源下功耗约为0.7mw。     

一种基于电平位移电路的低电压全摆幅CMOS运放

为解决阈值电压对电源电压和输入信号的受限问题,提出一种实用的电平位移电路,为运放的输入级提供良好的电平位移。采用互补金属氧化物半导体(CMOS)0.5μm工艺设计的低电压全摆幅CMOS运算放大器,中间级采用适合低电压工作的低压宽摆幅共源共栅结构,输出级采用传统的Class A类得到轨至轨的输出。采用Hspice软件对所设计的电路进行仿真。研究结果表明:当电源电压降至或者小于NMOS与PMOS的阈值电压之和时,在任何共模输入电压下,该运放都能正常工作,实现输入级的全摆幅和恒跨导;在1.3 V单电源供电情形下直流开环增益达106.5 dB,单位增益带宽为2.3 MHz,功耗178.8μW。电路结构简单紧凑,具有实用的电平位移功能,适合于低电压应用。     

锁相环高性能电荷泵电路的设计

设计了一种新型电荷泵电路,该电路采用了差分反相器,可工作在2 V的低电压下,具有速度快、波形平滑、结构简单、功耗低等特点.HSpice仿真结果显示,电荷泵的工作频率为10 MHz时,功耗仅为0.1 mW,输出信号的电压范围宽(0~2 V).该电路可广泛应用于差分低功耗锁相环电路中.     

一种用于锁相环的正反馈互补型电荷泵电路

给出了一种新型的互补型电荷泵电路．采用正反馈技术,电路由CSMC1．2μm CMOS工艺实现,可工作在2V的低电压下．Spectre仿真结果显示,电荷泵的工作频率为100MHz时,功耗为0．08mW,输出信号的电压范围宽(0～2V),电路速度快,波形平滑,抖动小,在不增加电路功耗的前提下消除了传统电荷泵电路的电压跳变现象．该电荷泵电路可以很好地应用于低电源电压、高频锁相环电路．     

低抖动高线性压控振荡器设计与仿真分析

设计一种应用于锁相环(PLL)电路的压控振荡器(VCO).该电路采用浮空电容结构,相对传统接地电容结构,可提高电容充放电幅值,减小时钟抖动.快速电平检测电路,使电路在未采用反馈和补偿的前提下,减小环路延时,从而实现高线性.电路采用CSMC 0.6 μm CMOS标准工艺库实现.仿真结果表明:振荡频率为0.79,24,30 MHz时的相位噪声达到-128,-122,-120 dBc·Hz^-1@1 MHz.通过调节外接电阻电容,使得电路在3~6 V电源电压下,输出100.0~3.0×10⁷ MHz的矩形波,电路兼具低相位噪声和高线性特性.     

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.     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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