基于四值脉冲参数模型的单粒子瞬态传播机理与软错误率分析方法

随着工艺尺寸的不断缩小,由单粒子瞬态(Single Event Transient, SET)效应引起的软错误已经成为影响宇航用深亚微米VLSI电路可靠性的主要威胁,而SET脉冲的产生和传播也成为电路软错误研究的热点问题。通过研究SET脉冲在逻辑链路中的传播发现：脉冲上升时间和下降时间的差异能够引起输出脉冲宽度的展宽或衰减;脉冲的宽度和幅度可决定其是否会被门的电气效应所屏蔽。该文提出一种四值脉冲参数模型可准确模拟SET脉冲形状,并采用结合查找表和经验公式的方法来模拟SET脉冲在电路中的传播过程。该文提出的四值脉冲参数模型可模拟SET脉冲在传播过程中的展宽和衰减效应,与单参数脉冲模型相比计算精度提高了2.4%。该文应用基于图的故障传播概率算法模拟SET脉冲传播过程中的逻辑屏蔽,可快速计算电路的软错误率。对ISCAS89及ISCAS85电路进行分析的实验结果表明：该方法与HSPICE仿真方法的平均偏差为4.12%,计算速度提升10000倍。该文方法可对大规模集成电路的软错误率进行快速分析。     

光测设备引导数据的误差分析

在光测设备实时数据处理过程中,往往容易碰到由于数学模型建立不准确或滤波参数取值不合适,导致数据滤波预测效果不理想的情况。为了能建立较为准确的数学模型,较好地配置滤波参数,从而提高设备的测量精度,提出了一种基于现代误差理论的数据分析方法。通过对引导数据应用最小二乘拟合残差法、隐周期辨识法和基于AR(p)模型的相关噪声估计法等,将实际引导数据分离成理想轨迹、隐周期噪声,相关噪声和白噪声;然后,综合理想轨迹和随机噪声选用合适的滤波器,通过理想轨迹建立实时数据处理的数学模型、通过各随机噪声确定各滤波参数估计值。显然,这种基于数据分析方法的滤波器选择和滤波参数确定是更有针对性的,与传统的滤波器选取和参数现场试凑方法相比,也更为有效。     

基于单片机的微弱信号测量及其数据传输

主要介绍了利用单片机AT89S8252实现对微弱电压量的检测,并进行无线数据通信的方法。该设计由原模拟传输改进为更可靠的数字传输方式,而且进一步将信号的传递用无线传输的方式实现,使得该方法在远距离遥测领域里得到了广泛的应用。因其选材的合理性使得该方法在应用过程中能适应各种恶劣的环境,并在直升机旋翼的提升力测量中得到很好的应用。     

Framework for Analysis of Transmission Rate Scheduling for Wireless CDMA Data Networks

The optimal utilization of network resources and the capacity to fulfill quality of service requirements are key requirements for 3rd G networks operations. Several burst admission and transmission rate scheduling algorithms are proposed in the literature. In this study, we develop an analytical framework for the downlink transmission rate scheduling problem for CDMA networks employing discrete service bit rates. The framework uses the average downlink transmit power as the system state and develops a K-dimensional Markov chain representing all possible states in the system. In addition, the transition probabilities due to arrivals of burst requests are made a function of the power utilization and the average power required to support the new burst taking into account the path loss model. The study assumes a transmission rate assignment scheme where the maximum possible system bit rate is assigned given the current system state and the subscriber’s eligibility profile for particular system service rates. The analytical model provides performance metrics such as system throughput, average power utilization, average number of simultaneous transmissions, burst request blocking probability, and mean burst service time. While the developed model is applicable for a general CDMA based network with arbitrary discrete system service bit rates, the model is evaluated for the example of a cdma2000 1xRTT network. A comparison between simulation and analytic results to assess the accuracy of the model is provided.

大口径细光束自准直测量系统的误差源分析

为了满足自准直系统的高精度要求,同时扩展其适用范围,以便更好地应用于科学研究,在光学自准直原理的基础上,针对大口径细光束的自准直系统进行研究,并对其误差源做了深入分析.对入射光束发散度引入的误差、CCD离焦误差、光学元件姿态引入的误差、反射镜平面度误差、准直系统瞄准误差以及原理误差这六种主要的误差源做了定量分析,同时对外界环境条件引入的误差进行了定性分析.通过对上述误差的定量与定性分析,可以直观地观察各误差源对系统精度产生的影响,为后续大口径细光束自准直系统的设计提供了重要的理论支持.     

一种用于海洋环境立体监测的数据传输系统

介绍了一种用于海洋环境立体监测的数据传输系统,主要从系统总体设计思路以及各部分实现方案两个方面进行了详述,该系统数据传输实时性较现有系统有所提升且使用方便,同时可对海事部门布放的原有浮标系统进行升级改造,成本相对较低,应用前景广泛。     

Error Rate and Capacity Analysis for Incremental Hybrid DAF Relaying using Polar Codes

The deployment of an incremental hybrid decode-amplify and forward relaying scheme is a promising and superior solution for cellular networks to meet ever-growing network traffic demands. However, the selection of a suitable relaying protocol based on the signal-to-noise ratio threshold is important in realizing an improved quality of service. In this paper, an incremental hybrid relaying protocol is proposed using polar codes. The proposed protocol achieves a better performance than existing turbo codes in terms of capacity. Simulation results show that the polar codes through an incremental hybrid decode-amplify-and-forward relay can provide a 38% gain when γ_th(1) and γ_th(2) are optimal. Further, the channel capacity is improved to 17.5 b/s/Hz and 23 b/s/Hz for 2 × 2 MIMO and 4 × 4 MIMO systems, respectively. Monte Carlo simulations are carried out to achieve the optimal solution.     

无线蜂窝环境下的统一移动模型及其接纳控制分析

提出了蜂窝结构下无线通信的一种统一用户移动模型,并给出了该模型下的接纳概率数学表达式.只要从不同的研究角度出发去合并或分解模型的某些参数,常见的几种移动模型都可以由该模型衍生出来.用带宽作为模型的资源参数,克服了以前接纳模型以信道数作为呼叫资源单位这种不适合分析数据通信的缺点.同时还总结了一种方法论思想,对研究系统性问题在思路上可能有所帮助.     

A new CAD tool for Single Event Transient Analysis and mitigation on Flash-based FPGAs

Flash-based Field Programmable Gate Array (FPGA) devices are nowadays golden core of many applications especially in space and avionic fields where reliability is an important concern. In particular, for Flash-based FPGAs, when adopted in those applications, the main concern is radiation-induced voltage glitches known as Single Event Transient (SET) in the combinational logic. In this work, a new CAD tool is presented for evaluating the sensitivity of the implemented circuit regarding SET and mitigating this effect. This tool has been applied to EUCLID space mission project including more than ten modules. The experimental results demonstrate the efficiency of the proposed tool.     

一种新的信源、信道编码和差错隐藏的联合优化方法

本文提出了一种基于广义的率失真函数的信源编码,信道编码和差错隐藏联合优化的方法.这种广义的率失真函数综合反映了视频信源经信源编码,信道编码,差错隐藏后的率失真特性,因此可以用来进行视频通信系统收发端的联合优化.仿真结果表明,和传统的信源信道联合编码算法相比,这种基于广义的率失真特性的联合优化可以取得更好的结果.     

A Novel Event Model for Performance Analysis of IEEE 802.11 DCF

After considering the memory effect among series events occurring on the channel, we propose a novel event model to analyze the channel status more precisely. The memory effect is caused by the backoff freezing regulation of IEEE 802.11 Distributed coordination function （DCF）, which has been ignored before and thus resulted in the inaccurate evaluation of the network performance. Based on our new event model, the network performance of IEEE 802.11 DCF, including throughput, packet delay distribution and energy efficiency is analyzed. Simulation results show that our model is highly accurate.     

锁相环敏感模块的单粒子效应与设计加固

应用于航天工程的锁相环(PLL)电路遭受太空高能粒子轰击时会发生单粒子效应(SEE),引起电路失锁,对系统造成灾难性影响.分析了鉴频鉴相器(PFD)和分频器(DIV)模块的单粒子效应导致失锁的机理,运用改进的双互锁结构(DICE)的锁存器和冗余触发器电路分别对其进行设计加固(RHBD),基于0.35μm CMOS工艺设计了加固的锁相环电路.仿真结果表明,加固PLL可以对输入20～40 MHz的信号完成锁定并稳定输出320～ 640 MHz的时钟信号.在250fC能量单粒子轰击下加固后PFD模块不会造成PLL失锁,加固DIV模块的敏感节点数目降低了80％.     

用太阳源测量UHF频段50 m天线增益及误差分析

简述了利用太阳源测量天线增益的基本公式,讨论了各种修正因子的计算方法.当50 m天线工作于611 MHz时,测量的天线增益为47.754 dBi,天线效率为58.25%,且测量的天线增益同理论增益吻合很好.最后,对增益测量误差进行了分析,其均方根误差小于或等于±0.29 dB.     

单二次雷达无线电干扰源定位算法及误差分析

为实现对无线电干扰源的精确定位,基于两部单二次雷达的空间坐标及时差参数,列出矩阵方程,求解该方程在欧氏范数空间下的最小范数解,以此得出无线电干扰源的空间坐标。而后借助两部雷达的原始视频,参照二维平面定位算法,并引入新的方位角概念,建立起两个辅助空间定位面;或依靠S模式接收机处理器的原始视频,完成误差分析和定位判别,由此证明可消除定位模糊。     

Analysis of Transmission Characteristics for Single and Double Disk Windows

The work reports about window design studies for both the JET EP ECRH project and the ASDEX-Upgrade ECRH system. Detailed calculations of the millimeter wave transmission characteristics for conventional single-disk windows, for frequency tunable double-disk windows and for ultra-broadband Brewster windows have been performed. The geometry of the window units has been optimized in order to obtain a suitable transmission characteristic, i.e. power reflection less than ?20 dB within a frequency bandwidth of about 1 GHz around the chosen frequencies. In particular the influence of mechanical tolerances on the transmission characteristic has been investigated in order to specify the mechanical dimensions of the CVD-diamond disks and the window unit. In case of a Brewster window, the thickness has been optimized to get low power reflection over a wide angles range around the Brewster angle.     

桥梁无线应变测量系统数据传输的设计与实现

桥梁应变无线测量系统使用单片机、调制解调器FX429等主要器件，在可靠的通信协议下，采用无线方式实现了主控节点和各远端数据采集节点之间的数据传输。大大提高了测试系统的方便性、机动性和灵活性，进而提高了整个测试工作效率。     

简化Markov模型的可靠性分析

Markov模型是电子产品系统可靠性分析中最常使用的方法。但在应用Markov模型的时候一个主要的问题是它的巨大的状态数，使得它对复杂系统的建模和分析变得非常困难。本文提出了一种新的简化Markov模型的方法来简化对系统可靠性的分析。并且对该简化方法的误差界限进行了讨论。数值仿真结果表明了该方法的有效性。     

数字信号信道模型的模拟和多径效应脉冲展宽的测量

利用简化的散射信道模型对数字移动通信信道进行计算机模拟,可模拟出不同反射路径、不同时延的多径信号波形。利用通用仪表和软件相结合的方法,在北京市区和近郊区进行多径效应脉冲展宽的实际测量,结果表明多径时延值符合对数正态分布。     

Exact Error Rate Analysis of MIMO-MRC System under Cochannel Interference and Imperfect Channel State Information

In this paper, we derive closed-form solution for the bit error rate of multi-input multi-output (MIMO) system with maximum ratio combining. We consider binary PSK modulation suffers from cochannel interference (CCI) and imperfect channel state information (CSI). We assume a propagation model wherein the desired and interfering signals undergo independent and identically distributed (i.i.d.) Rayleigh fading channels. Furthermore, the signal-to-noise ratio (SNR) gain penalty caused by the interference signals and the root mean square of the CSI were demonstrated. The numerical results presented in this paper demonstrate the system performance under very realistic propagation and detection conditions including MIMO system, CCI, imperfect CSI, generalized fading channels, and AWGN. Hence our results are expected to be of significant practical use for such scenarios.     

测量误差的判定分析与计算及其应用

简述了误差的定义,根据工作经验,举例说明误差理论的应用效果,并就如何分析、判别、确定误差及计算方法进行了介绍,以此来提高测量的精度及准确性,使误差得到正确的处理,提高误差理论在实际工作中的应用水平.