一种基于自偏置技术的低功耗锁相环设计

采用TSMC 0.13 μm CMOS工艺,设计并实现了一种低功耗、具有固定的环路带宽与工作频率之比,以及良好相位噪声性能的自偏置锁相环(PLL)芯片电路。仿真结果表明,该PLL电路工作频率范围为200~800 MHz,在480 MHz输出频率的相位噪声为-108 dBc@1 MHz,1.2 V电源供电下消耗功耗2 mW。芯片核心电路面积仅为0.15 mm²,非常适合应用于系统集成。     

一种自适应带宽低抖动PLL设计

设计了一种宽调节范围自适应带宽的低抖动锁相环倍频器(PLL)。通过采用自偏置技术,使得电荷泵电流和运算放大器的输出阻抗随工作频率成比例变化,从而使阻尼因子保持固定、环路带宽跟随输入参考频率自动调整,以及PLL在整个输出频率范围内保持最佳的抖动性能。电路采用SMIC 0.18 μm CMOS工艺进行设计,后仿真验证表明,该PLL电路能够在0.35~2.1 GHz的输出频率范围内输出良好的低抖动信号,输出频率为2.1 GHz时,均方根抖动为2.47 ps。     

一种用于LVDS驱动器的PLL时钟倍频器的设计

设计了一个结构新颖的3.5倍频锁相环(PLL)倍频器,该电路应用自适应电荷泵和压控振荡器工作频率范围复用技术,调整环路带宽,减小压控振荡器的工作范围.采用1st Silicon 0.25 μm CMOS混合信号工艺仿真.结果表明,PLL倍频器具有较低的噪声和较高的捕获速度.     

基于DDS 与PLL 的C 波段宽带线性扫频源

利用直接数字频率合成(DDS)和锁相环(PLL)技术相结合的混合频率合成方案,研制了一种C波段宽带、高频率分辨率、快速线性扫频的频率源。为了给PLL 提供低相位噪声的宽带扫频参考信号,选用ADI 的DDS芯片AD9914,并利用阶跃恢复二极管(SRD)高次倍频电路结合二倍频器产生高达3400 MHz 的时钟信号。通过上位机配置AD9914 内部频率调谐字和数字斜坡发生器,产生512.5-987.5MHz 的扫频参考信号,其频率分辨率可精细到赫兹量级。选用低附加噪声的鉴相器和宽带VCO 芯片设计C 波段锁相源,在宽带工作频率范围内对DDS 扫频信号进行快速跟踪,并有效抑制杂散信号。实测结果表明,该扫频源工作频率为4. 1- 7. 9 GHz,在频率分辨率配置为0. 38 MHz 时,单向扫频周期为1 ms,扫频线性度为1. 58×10-6 。单频点输出时相位噪声优于-114 dBc/ Hz@ 10 kHz和-119 dBc/ Hz@ 100 kHz,杂散抑制优于69 dBc。     

一种通用宽带FM解调电路的设计

实现了一款可用于卫星接收系统中频段电视信号的解调电路.该芯片的设计基于BiC-MOS工艺.采用5 V电源电压供电,利用单片锁相环(PLL)实现宽带FM解调,外围器件只包括本地振荡维持网络和环路反馈元件,PLL工作频率可达800 MHz.芯片内部还集成了自动增益控制(AGC)、模拟自动频率控制(AFC)模块.该芯片具有较高的信号接收灵敏度.     

超声波焊接机频率跟踪控制的一种方法

用检相法测试出换能器输出电压和电流相位差的值和滞后/超前情况作为超声波焊接机工作频率调整信号,通过磁饱和原理和数字电位器改变线圈电场强度来改变其电感值(即改变电路工作频率)从而跟踪控制频率使电路回到谐振状态.本文讲述了频率控制原理,给出了实现电路和测试数据,证明了此方法是可行的.     

AT89C2051控制LMX2332的频率合成器

LMX2332是美国国家半导体公司生产的集成数字锁相环(PLL)电路。文章介绍了利用单片机AT89C2051控制数字锁相环LMX2332及压控振荡器JTOS -150实现低噪声频率源的方法 ,该方法可通过改变AT89C2051的程序得到不同频率的信号。     

一种新颖的星载宽带频率源设计

针对应用于复杂空间环境的宽带接收机的需求,提出了一种新颖的频率源设计方案.采用锁相环(PLL)和倍频电路实现宽带频综,采用直接数字频率合成器(DDS)实现窄带细步进频综.给出了频率源的详细设计思路、实现方法及可靠性设计的相关内容,实测结果表明所设计的频率源各项指标均满足要求.     

基于TSPC的4/5双模前置分频器设计

针对无线传感网络对射频电路高速、低功耗方面日益增长的性能要求,设计了一款用于高频锁相环中的高速、低功耗4/5双模前置分频器。在分析真单相时钟(TSPC)电路工作原理的基础上,指出了该电路结构存在的两个主要缺点,并结合器件工艺和物理给出了相应的版图优化解决方法。然后,采用SMIC 0.18μm标准CMOS工艺,设计了一款基于这种改进后的真单相时钟电路的集成4/5双模前置分频器。在版图优化设计后利用Cadence Spectre进行了后仿真验证,结果表明,在直流电源电压1.8 V时,该4/5双模前置分频器的最高工作频率可达到3.4 GHz,总功耗仅有0.80 mW。该4/5双模前置分频器的最低输入幅值为0.2 V时,工作频率范围为20 MHz~2.5 GHz,能够满足面向无线传感网络应用的锁相环(PLL)的高速、低功耗性能要求。     

一种基于PLL同步的循环周期脉冲信号计量方法

详细分析了循环周期脉冲信号异步测量方法的计量误差,指出了影响测控系统计量精度的主要原因,提出了基于锁相环(PLL)同步的新方法。该方法能有效消除测控系统的计量误差随传感器工作状态变化的因素,在PLL内部计数频率高于系统CPU工作频率的情况下,可以有效提高系统的计量精度,同时,可以自动实现传感器测量信号的归一化运算,避免CPU的除法运算负担,从而有效提高测控系统的实时性。最后给出了具体应用PLL同步计量方法的实用测量接口电路。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.