Novel Type of Wide\|Bandwidth GaAs/AlGaAs Infrared Photodetectors

A novel asymmetrical GaAs/AlGaAs photoconductance infrared detector based on the new idea proposed in this paper has been developed,which uses the intersubband transition within the same conduction (valence) band due to infrared radiation.The detectors with two wells or six wells grown by Metalorganic Chemical Vapor Deposition (MOCVD) system are fabricated by etching a mesa size of 200μm×200μm.Evident infrared absorption on the wavelength from 5 to 10μm has been observed for two samples,so has the peak of negative differential conductance.It is demonstrated that the photocurrent together with the signal\|to\|noise ratio increases with the number of the wells,but have nothing to do with the increase of the noise current under the same electric field,i.e.,the voltage drops per period,as is different from the conventional GaAs/AlGaAs Quantum Well Infrared Photodetectors (QWIPs).The noise current is one order's magnitude lower than that of the conventional GaAs/AlGaAs QWIPs.It is anticipated that the photocurrent and detector performances can be improved further by increasing the number of wells and optimizing the structural parameters.     

X25165芯片在8051系统中的应用

Ｘ２５１６５是美国Ｘｉｃｏｒ公司生产的集看门狗、电压监控和串行ＥＥＰＲＯＭ于一体的专用集成电路。文中介绍了Ｘ２５１６５的结构,功能及工作原理,并以其在８０５１系统中的应用实例,给出了Ｘ２５１６５与８０５１单片机的硬件接口电路和软件接口程序。     

逆层析彩虹全息光路参数与色差分析

本文应用横向面积分割和非相干多次曝光相结合的方法在一幅合成彩虹全息图上记录 10～ 6 0片CT平面断层图象 ,并提出了各层再现像亮度均匀、颜色相近的光路设计方法。本文还对白光再现像的色差进行了讨论。     

砷化镓单晶片抛光工艺研究

由于砷化镓（ＧａＡｓ）及其它化合物半导体具有很重要的作用，目前对它们的工艺研究越来越多。本文主要介绍了一种比较成熟的ＧａＡｓ单晶片抛光工艺。     

SnO2：TiO2薄膜氨气敏光纤传感器的研究

本文作者利用ＳｎＯ２：ＴｉＯ２气敏光学薄膜设计制成气敏光纤传感器，并用它测定氨蒸汽浓度，传感器的灵敏范围为１５０￣６０００ｐｐｍ，灵敏度为２００ｐｐｍ。     

测控电路设计中运算放大器的若干误用

运算放大器(运放)在测控电路中有重要而广泛的应用,已成为测控电路中的基本器件.测控电路的特点对运放的应用设计有更高的要求.在测控电路设计中,往往因运放的应用设计不当或错误而降低电路的性能,甚至电路不能正常工作.总结了在测控电路设计中运放的几种重要误用,分析了其原因,并给出了相应的对策.相关的讨论与结论对运放在测控电路中的应用设计具有参考作用.     

集成宽带VCO的低相噪设计

从VCO的相位噪声概念及原理分析入手,论述了集成宽带压控振荡器低相噪的设计方法和设计思路,进行了理论分析和数学模拟,并通过利用相关软件进行仿真、优化设计。获得了低相噪声的宽带振荡器,并给出了各频段集成宽带VCO最终达到的相位噪声指标。低相噪声集成VCO系列产品的成功研制极大地方便了系统设计师的电路设计,该自主研制的低相噪VCO已广泛应用于多种电子系统中,对系统关键电路的国产化、高性能化有着重要意义。     

Probabilistically bounded soft sphere detection for MIMO-OFDM receivers: algorithm and system architecture

Iterative soft detection and channel decoding for MIMO OFDM downlink receivers is studied in this work. Proposed inner soft sphere detection employs a variable upper bound for number of candidates per transmit antenna and utilizes the breath-first candidate-search algorithm. Upper bounds are based on probability distribution of the number of candidates found inside the spherical region formed around the received symbolvector. Detection accuracy of unbounded breadth-first candidatesearch is preserved while significant reduction of the search latency and area cost is achieved. This probabilistically bounded candidate-search algorithm improves error-rate performance of non-probabilistically bounded soft sphere detection algorithms, while providing smaller detection latency with same hardware resources. Prototype architecture of soft sphere detector is synthesized on Xilinx FPGA and for an ASIC design. Using area-cost of a single soft sphere detector, a level of processing parallelism required to achieve targeted high data rates for future wireless systems (for example, 1 Gbps data rate) is determined.     

九洲高压变频器在苏丹吉里电站锅炉给水中的应用

本文介绍了国产高压变频器在苏丹吉里火电厂锅炉给水泵中的应用,并详细描述了变频调速下的节能情况,以及在特殊环境中遇到的问题及解决方案。     

动态聚类算法在网络入侵检测中的应用

为了进一步提高网络入侵检测技术的检测率,降低误报率和漏报率.针对普通聚类算法存在的聚类结果对随机选取初始聚类中心敏感、分类结果不稳定,从而造成的检测率低、漏报和误报率高的特点.提出一种基于动态聚类算法的网络入侵检测模型,实验结果表明通过在K-均值聚类算法的基础上增加动态迭代调整聚类中心,使聚类结果更稳定更准确.与K-均值聚类等算法相比提高了网络入侵检测的性能,从而表明该算法的可行性,有效性.