基于软件无线电跳频电台射频前端的研究

基于软件无线电的基本要求和发展趋势,提出了一种应用在软件无线电跳频电台中宽频段接收机的前端电路设计方案,分析了接收机射频前端二次混频方案结构的可行性,在对方案中各功能模块研究分析的基础上,完成了射频前端的滤波嚣、混频器、放大器等各模块的设计工作,并对整个系统进行了建模设计和仿真验证.仿真结果表明,接收机前端电路噪声系数...     

基于软件无线电跳频电台射频前端的研究

基于软件无线电的基本要求和发展趋势,提出了一种应用在软件无线电跳频电台中宽频段接收机的前端电路设计方案,分析了接收机射频前端二次混频方案结构的可行性,在对方案中各功能模块研究分析的基础上,完成了射频前端的滤波器、混频器、放大器等各模块的设计工作,并对整个系统进行了建模设计和仿真验证。仿真结果表明,接收机前端电路噪声系数低,镜像抑制良好,增益合理,选择性合适,均满足设计要求。     

用HP-EESOF软件分析接收机的互调失真

本文介绍了应用Agilent公司的Advanced Design System软件对短波监测接收机前端射频电路的互调失真进行仿真，包括如何建模及仿真过程等，并把仿真的结果与实际测量结果进行了比较。     

VHF跳频电台接收机射频前端的仿真设计与研究

通过对VHF跳频电台接收机射频前端设计指标和具体结构的介绍,运用Agilent公司的射频设计仿真软件ADS,对整个接收机射频前端电路进行仿真和电路设计,构建了一个由保护电路、跳频预选滤波器、低噪声放大器和自动增益控制电路组成的射频前端电路模型,并对其进行仿真.最后的实验结果表明,所设计的射频前端的性能指标达到了系统的设计要求,并有所提高.     

基于Vega的红外视景仿真技术

介绍了基于Visual C++和Multigen Vega环境开发虚拟现实仿真系统的方法.该方法首先使用Creator软件建立带纹理的三维模型,然后使用TMM和MOSART工具分别对红外纹理和大气环境进行建模,最后使用Vega传感器模块进行红外图像仿真.基于Visual C++集成开发环境,应用Vega API编程技术...     

2．4GHz收发系统射频前端的ADS设计与仿真

针对无线移动通信环境中的应用,使用ADS软件设计了一种2.4 GHz收发系统的射频前端,射频前端中的关键模块均根据实际的集成射频模块的参数设计.使用ADS软件对设计的射频前端进行预算仿真、S参数仿真、大信号S参数仿真、谐波平衡仿真等.由仿真可以得出射频发送端的总增益为17.783 dB,效率为16%.接收端的灵敏度为-92.08 dBm,带宽为6 MHz.仿真结果表明,设计的射频前端符合实际的无线移动通信环境的要求.     

RFID发射前端的零中频电路设计

软件无线电技术增强了射频识别（RFID）系统的信号处理能力及兼容性,而零中频的设计思想进一步简化了射频前端结构。然而射频前端依然发挥着不可替代之重要功能,若在设计中将其地位置于软件子系统之下往往会恶化整体性能。本文对基于零中频技术的RFID射频发射前端进行了必要的理论分析,在此基础上,按照性能指标要求对系统进行了预增益仿真和谐波平衡仿真,以此作为模块选型和优化的依据,最后完成了射频前端设计。仿真结果表明,各项指标较为理想。     

基于软件无线电宽带接收机研究与仿真

针对软件无线电系统的灵活性,要求射频前端接收机能够工作在相当宽的频率范围.提出了一种应用在软件无线电电台的宽频段接收机的设计方案,分析了3次混频方案的合理性,详细描述了方案中各模块的作用,并对整个系统进行了建模和仿真验证.系统仿真性能显示该方案具有良好的选择性、中频增益和小于5 dB的噪声系数.     

宽带一体化接收前端技术的研究

本文构建了一个通用化、标准化、模块化的带射频接收前端,结合指标要求,进行了系统指标的规划及方案 的可行性论证,利用ADS 软件对其关键指标进行了仿真验证,阐述了宽带射端的设计方法及步骤。通过对各个功能模 块的设计、选择、及调试,最终在200MHz-3200MHz 的频率范围内,采用二次变频技术设计了一种超外差接收前端。 介绍了宽带射频前端系统仿真研究、接收机系统的方案选择、大动态范围接收机的实现接收机技术指标的计算与仿真 和发射机系统的设计与仿真。介绍了宽带一体化接收前端技术的系统设计与实现以及2～6GHz 通用接收机研究及关键 电路的设计与实验。     

连续波多普勒测速雷达射频前端电路设计与仿真

介绍了微波测速雷达的基本原理与结构模型,提出了频率为950 MHz的连续波多普勒测速雷达射频前端收发电路的设计方法,并对该电路的振荡条件,混频特性,放大原理进行了详细分析。利用OrCAD／PSpice9．2仿真软件,对射频电路收发系统进行仿真分析,仿真结果进一步验证了电路设计的合理性和可行性。     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.