多系统组合定位几何精度因子分析

卫星导航多系统组合定位技术可以充分发挥各个卫星导航系统的优势，能够大大提高系统的可用性、连续性、可靠性和精度。本文主要对组合定位方式下的几何精度因子进行详细分析，这对多系统组合定位技术的研究具有一定的实际意义和参考价值。     

嵌入式脉象采集仪电路设计

该脉象采集仪采用IP核技术、SoPC技术,将脉象采集的大部分功能都集成在一片FPGA内部,并自主进行了脉象采集控制的FPGA设计。该设计采用在SoPC系统外做控制电路部分,三路脉搏信号共用一个ADC,只需要很少的外部器件就能实现。与早期采用工控机、PC机,或者现在多采用的ARM设计方法相比,该脉象采集仪具有成本低,功耗低,体积小,便于扩展,稳定性高和系统维护方便等优点。     

气相法掺铅钛酸钡薄膜的微观形态变化

Ba（1-x）PbxTiO3是重要的电子陶瓷材料，具有优良的电学性能。而Ba（1-x）PbxTiO3薄膜更是重要的电子元件材料。薄膜材料一般是通过离子溅射、等离子体法、溶胶、凝胶法、气相淀积等工艺制备的，这些工艺各有优缺点，主要是可操作性和薄膜的质量问题。我们采用一种新型的气相掺杂工艺，即先利用溶胶-凝胶法或水絷沉积法得到纳米钛酸钡薄膜，然后用气相法进行掺杂处理，得到不同掺铅量的薄膜。     

基于AHP的新型雷达装备战斗力灰色评估模型

新型雷达装备战斗力评估是一个十分复杂的问题,涉及因素多,而且部分因素存在信息不完全和不确定的问题,而灰色系统理论是处理这类问题的有力工具.文中提出了利用灰色系统的相关理论来评估新型雷达装备战斗力,建立了基于层次结构的灰色评估指标体系,介绍了灰色评估模型和评估算法,通过仿真评估举例,结果表明该方法简单有效,为新型雷达装备战斗力评价理论的发展提供了新的思路.     

压电陶瓷光纤相位调制控制系统的研制

压电陶瓷光纤相位调制器是光纤傅里叶变换光谱测量系统中的核心器件之一,压电陶瓷驱动控制系统的输出电压特性决定了压电陶瓷光纤相位调制器的多种性能,如线性、分辨率、动态特性等,从而对光纤傅里叶变换光谱测量系统的光谱分辨率、测量速度和系统噪声等重要指标产生影响.应用复杂可编程逻辑器件(CPLD)、复合高压运放和单片机等先进电子技术设计压电陶瓷光纤相位调制控制系统.实验表明,该系统加载压电陶瓷容性负载后,在设定的频率范围内显示出了较好的动态特性与线形度,能很好地满足光纤相位调制技术对压电陶瓷工作电压波形的要求.     

一种嵌入式PC的高速数据采集系统

介绍了一种嵌入式PC的高速模拟信号数据采集系统，结合已开发的工业管材超声波检洲仪器，介绍了该系统的硬件、软件组成；叙述了一种利用双端口RAM，实现高速信号采集自动化的原理和方法。     

Characterization and profile optimization of SiGe pFETs onsilicon-on-sapphire

We present the details of the fabrication, electrical characterization, and profile optimization of a SiGe pFET on silicon-on-sapphire (SOS) technology. The results show that the SiGe pFETs have higher low-field mobility (μ_eff), transconductance (g_m), and cutoff frequency (f_T) than a comparable Si pFET. At low temperature (85 K), a secondary peak is observed in the linear g_m of the SiGe pFETs and is attributed to hole confinement in the SiGe channel. The effect of reducing the SOS film thickness on the mobility and short-channel performance is studied. A low-frequency noise study shows significant improvement in the SiGe pPETs over comparable Si pFETs, and is attributed to a lower sampling of interface trap density caused by the band offset at the oxide interface due to SiGe. Drain Induced Back Channel Inversion (DIBCI) is shown to occur in short gate length devices, resulting in high off-state leakage current through conduction at the back silicon-sapphire interface. The paper also discusses important optimization issues in the design of 0.25-μm gate length SiGe pFETs. A novel structure is proposed which optimizes the threshold voltage, maximizes hole confinement gate voltage range and cutoff frequency, while at the same time minimizing DIBCI to make the design usable to gate lengths as short as 0.25 μm     

大规模RapidIO协议交换的FPGA实现

RapidIO交换模块是RapidIO系统的核心模块,决定了整个RapidIO系统的数据带宽.文中介绍了一种大规模RapidIO协议交换的FPGA实现方式,并且在基于VPX总线的RapidIO交换模块中得到实际应用.该交换模块除具有RapidIO协议交换功能,还具有RapidIO系统主控功能以及以太网交换功能.经过使用实际的RapidIO端点模块进行测试,该交换模块实现了RapidIO交换功能以及RapidIO系统主控功能.     

An adaptive algorithm for connecting mobile ad hoc network to Internet with unidirectional links supported

The performance of Internet connectivity is degraded dramatically by blind rebroadcast of gateway discovery packets when obvious unidirectional links are ignored. To overcome this problem, an effective adaptive gateway discovery algorithm for connecting mobile ad hoc network to Internet with unidirectional links supported is proposed in this paper. On the basis of modification for ad hoc on-demand distance vector (AODV), through rebroadcasting the gateway discovery messages and gateway advertisement messages, both of which are extended with local connection information, unidirectional links are successfully removed from global route computations and Internet connectivity is simultaneously enhanced. Furthermore, an adaptive Internet working scheme is adopted to provide the best coverage of gateway advertisement according to dynamically adjusting broadcast range and sending interval of gateway advertisement messages in terms of network conditions. Simulation results show that the proposed hybrid Internet connectivity algorithm can provide better connectivity performance due to avoiding unidirectional links effectively with reasonable overhead.