生命探测雷达环境动目标的干扰抑制研究

生命探测雷达在实际探测中,由于环境中动目标的存在而对探测系统造成一定的干扰,致使雷达的探测准确性降低。本文搭建了基于双天线的连续波生命探测雷达实验平台,提出了将互相关无偏估计方法应用于生命探测过程中的环境动目标干扰抑制,并进行了实际探测实验,给出了结果。所采信号及处理结果表明该方法适用于生命探测雷达环境中动目标的干扰抑制。     

大规模多业务网络中几个关键问题的分析

随着网络规模的不断扩大和业务的不断涌现，一些在网络建设初期没有予以足够重视的问题已日益变得突出。文章针对其中几个关键问题进行了分析，并提出了解决思路。     

采用信息融合技术的IR／MMW复合导引头的目标跟踪

从误差测量环节入手，基于IR／MMW双模结构，采用信息融合处理技术提高其估计跟踪精度，最终达到降低制导误差，提高武器性能的目的，仿真结果验证了该方法的有效性。     

HPRF脉冲多普勒频率步进雷达信号处理与参数设计

频率步进雷达是一种距离高分辨雷达,传统的处理方法是采用频时转换(IDFT)获得目标的一维距离像,实际上其处理也可以采用时频转换(DFT)的方式进行,这时也可把频率步进雷达看作是一种载频跳变的脉冲多普勒(PD)雷达.采用这种分析方法的优点是,在高重复频率(HPRF)的情况下,可以通过雷达系统的参数设计和信号处理,同时获得不模糊的测速性能和距离高分辨性能,并解决HPRF PD雷达的距离模糊问题.本论文在分析频率步进雷达时频转换(DFT)处理的基础上,给出了HPRF PD频率步进雷达系统参数设计准则及频时耦合的解决方法,以及距离模糊问题的解决方案.理论分析和仿真结果证明,这种雷达体制可以同时获得不模糊测速和距离高分辨性能.     

Centralized and distributed power control algorithms for multimedia CDMA networks

We study in this paper both centralized and distributed transmitter power control algorithms for multimedia CDMA networks. In our study, users can have different data rates as well as different quality of service (QoS) requirements characterized by bit energy‐to‐interference ratios. For centralized power control, we derive an optimum power assignment which can be obtained by solving a set of linear equations. For distributed power control (DPC), we study the fully distributed power control (FDPC) algorithm. We modify the FDPC algorithm so that it can be used in a multi‐service environment. We prove that, as long as there are solutions of power levels for all users to meet their QoS requirements, the FDPC algorithm can always find one. A quasi‐centralized power control algorithm with partial link gain measurements is proposed to speed up the process in finding a feasible power set. In the algorithm, a base station measures the link gains for all mobiles connected to it. Numerical results show that quasi‐centralized power control can find a feasible power set much faster than distributed power control. Copyright © 2005 John Wiley & Sons, Ltd.     

硅基1.55μm共振腔增强型探测器

报道了一种利用硅乳胶作为键合介质的新型键合技术.高反射率的SiO2/Si反射镜预先用PECVD系统生长在硅片上,然后键合到InGaAs有源区上,键合温度为350℃,无需特殊表面处理,反射镜的反射率可以高达99.9%以上,制作工艺简单,价格便宜.并获得硅基峰值响应波长为1.54μm,量子效率达22.6%的窄带响应,峰值半高宽为27nm.本方法有望用于工业生产.     

A Built-in Self-Test Scheme with Diagnostics Support for Embedded SRAM

In this paper we propose a novel built-in self-test (BIST) design for embedded SRAM cores. Our contribution includes a compact and efficient BIST circuit with diagnosis support and an automatic diagnostic system. The diagnosis module of our BIST circuit can capture the error syndromes as well as fault locations for the purposes of repair and fault/failure analysis. In addition, our design provides programmability for custom March algorithms with lower hardware cost. The combination of the on-line programming mode and diagnostic system dramatically reduces the effort in design debugging and yield enhancement. We have designed and implemented test chips with our BIST design. Experimental results show that the area overhead of the proposed BIST design is only 2.4% for a 128 KB SRAM, and 0.65% for a 2 MB one.     

Information technology innovations: general diffusion patterns andits relationships to innovation characteristics

While many scholars of organizational innovations have examined characteristics of innovations such as relative advantage and complexity and how they facilitate the adoption of an innovation by organizations, others have used mathematical models to fit diffusion patterns. In this study, the authors attempt to integrate these two areas of inquiry and explore the possibilities to predict diffusion patterns based on characteristics of the innovation and the adopting entities. Based on a cross-sectional sample of 313 large American firms, 20 information technology (IT) innovations were examined and their diffusion patterns assessed with respect to models that espoused internal and external influence. The mixed influence model (Bass model) was chosen as a robust common representation for the set of diffusion patterns. However, the external influence as represented by the coefficient of innovation was found to be extremely small and the internal influence dominates for all innovations. The other two parameters of the model, the saturation level and the coefficient of imitation, which represents internal influence, were then used to perform a cluster analysis. Five clusters of technologies emerged, and the potential relationships between their innovation characteristics and diffusion patterns were explored. Rigorous examination of these potential relationships by future researchers may result in practical methods for predicting patterns of IT innovation diffusion based on innovation and technology characteristics     

迈向纳米级芯片技术的IMEC研发——先进封装技术部分

近期、芯片制造工艺发展到了纳米时代(栅极宽度<100nm),IM E C发起并联合了全球七家主要半导体芯片制造商和几乎所有主要设备制造商,在刚建立起来的φ300m m硅片尺寸工艺中试线上,共同展开了45nm和32nm的芯片制造工艺的研究工作。虽然芯片封装技术也在快速发展,但其速度赶不上芯片制造工艺的迅猛发展。在先进的芯片制造技术和最新的PCB技术之间所谓的“互连技术壕沟”在不断扩大。而且,不断增加的工作频率,以及由于集成电路复杂程度提高而导致I O管脚的增加,都要求封装技术产生重大的技术变革,以保证在将纳米级的芯片与毫米级的系统相连…     

一种新型脉冲负载对电网运行的影响规律

雷达中含有大量的电力电子元件,供电系统结构复杂。文中以现有雷达负载模型为基础,考虑了雷达负载中的降压部分,提出一种将相控阵雷达结构简化为整流降压变换器、直流开关、脉冲负载三个模块的新型脉冲负载结构及模拟方法;推导了新型脉冲负载的数学模型;通过仿真分析了脉冲负载参数占空比D、峰值功率PL、周期TS变化对电网运行规律的影响;通过搭建实验平台验证了仿真分析的正确性。