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服务器高速电路中几乎离不开过孔,过孔性能在液冷环境中与风冷环境中存在差异。在HFSS中建立差分过孔三维模型,仿真了风冷环境中过孔的阻抗和串扰情况,在液冷环境中过孔的阻抗和串扰情况。仿真结果表明:微带线在液体中阻抗比在空气中阻抗低5 ohm左右;过孔表层焊盘处在液体中阻抗比在空气中阻抗低4.5 ohm左右;过孔孔径处在液体中阻抗比在空气中阻抗低0.5 ohm左右;在液体中的过孔间串扰与在空气中的过孔间串扰相差不足1 dB。针对液冷服务器中过孔性能,从阻抗和串扰两个角度进行了仿真分析,同一过孔需分别应用在空气和液体环境中,可通过优化反焊盘,适当降低过孔孔径处的阻抗,以缓解因阻抗不连续引起的反射问题。在液体中过孔间的串扰与在空气中过孔间的串扰基本一致,在过孔间距无法改变的情况下,可以通过增加液冷服务器过孔间回流地孔的个数,降低过孔间串扰。 相似文献
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随着高速数字微系统中DDR总线信号传输速率与系统集成度的不断提高,过孔串扰问题成为影响系统信号完整性的不可忽视的因素之一。基于电磁耦合理论,通过建模仿真方法量化分析了过孔串扰的主要影响因素以及串扰噪声对信号质量的影响,在此基础上提出了过孔设计的主要原则以及减小串扰噪声的优化设计方法;介绍了一种正反面腔体结构系统级封装的信号处理微系统基板,结合JEDEC标准对DDR3总线进行了仿真分析与评估,通过以上方法优化过孔串扰大大改善了DDR总线的信号完整性,验证了该方法的正确性与有效性。 相似文献
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随着SERDES传输速率达到10Gbps,高速PCB上的信号传输尤其是多板间传输,已经成为高速设计的实现难点。高速PCB及其要素的设计、分析、仿真,以及高速传输链路的设计优化,是多板SERDES传输实现更高速率的关键。本文对高速串行SERDES的原理和架构进行了深入分析,研究了多板传输中影响信号完整性(SI)的关键因素和建模优化方法;最后,针对实验电路板建立了多板仿真模型,对实际的SERDES差分网络进行了仿真分析。 相似文献
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为应对航空电子系统高速化、高集成度发展方向的要求,印制电路板作为电子系统的基石能够实现良好的信号完整性,以提升电子系统的性能与稳定性,深入分析了导致高速印制电路板出现信号完整性问题的两个主要因素,提出了相应的解决措施,并利用仿真工具Sigrity PowerSI对高速印制电路板的布线进行仿真优化,最终有效改善了高速PC... 相似文献
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新一代高性能计算机的高速信号传输系统采用56 Gbps PAM4信号实现,传输通道跨越多块PCB板和多级连接器,信号完整性设计面临极大挑战。提出了面向全通道的56 Gbps高速信号传输系统仿真验证方案,通过板材参数校准、连接器参数测试、PCB布线模型提取,建立了更接近实际情况的复杂传输通道模型,并进行了全通道协同仿真实验。通过仿真实验与设计优化迭代,成功保障了56 Gbps PAM4高速信号的稳定可靠传输。 相似文献
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雷达高速数字电路模块(基于VPX总线)的高速数字接口测试过程中,针对出现的高速数字信号质量不理想的问题,分析了该现象出现的原因并最终提出了保证测试过程中高速信号的信号完整性的解决方案:在高速信号连接电路设计中避免出现多个终端输出。实验结果表明,高速信号接口单一输出端的高速信号质量相比多个输出端的信号质量有明显改善,信号误码率优化了e10倍;通过眼图测量,信号速率为1.25Gbps时单一输出端的高速信号眼高为8.9uW,眼宽为730ps,多个输出端的信号已经无法形成眼图。验证了高速数字信号测试时为了保证信号完整性应避免出现多个终端输出的正确性。 相似文献
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高速PCB的仿真技术 总被引:3,自引:0,他引:3
利用IBIS模型进行板级信号完整性分析是一种简单、易用的分析方法。结合PCB设计的SI模型,介绍了几种板级信号完整性分析的方法,讨论了各种分析方法的利弊,确定了使用IBIS模型进行信号完整性分析和EMC分析。通过加载IBIS模型对P4主板的DDR信号线进行了仿真,并对仿真结果进行了分析,达到了验证设计规范的目的。 相似文献
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Some combinatorial stochastic resource allocation problems lack algebraically defined objective functions and hence require optimization via simulation as a mechanism for obtaining good solutions. For this class of problems, we propose a new predictor-based heuristic that uses a distance criterion to perform the solution search. To demonstrate our solution approach, we apply this heuristic to the problem of selecting the proper design configuration of an unmanned aerial system (UAS) fleet so as to maximize mission effectiveness. We compare our approach to black box optimization via simulation approaches (two tabu search-based procedures and a greedy heuristic) and glean both methodological and practical insights. 相似文献
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针对传统遥感卫星传输系统中采用低阶固定调制编码(CCM)以及不能及时将信道状态反馈给发送端的问题,结合第二代数字广播电视(DVB-S2)的自适应编码调制(ACM)技术和基于卫星回传信道的数字广播电视(DVB-RCS)中的RCS技术,将其应用在遥感卫星传输系统中。同时,针对遥感数据信号受雨衰影响严重的问题,将可变降雨备余量的方法引入到链路预算中,分析结果表示,与传统固定降雨备余量相比传输数据量提高了1.21倍,与CCM相比提高了2.01倍。通过卫星工具包(STK),对基于RCS的遥感数据传输系统进行了模拟过境回传仿真,分别从信道回传方式、延迟以及雨衰备余量三个方面进行了分析,仿真结果验证了方案的正确性和有效性。 相似文献
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Multi-objectivization via Segmentation (MOS) has been shown to give improved results over other previous multi-objectivization approaches. This paper explores the mechanisms that make different segmentations in MOS successful in the context of the Traveling Salesman Problem (TSP). A variety of new segmentation methods are analyzed and theories regarding their performance are presented. Spatial segmentation methods are compared with other adaptive and static decomposition methods. Insight into why previous adaptive methods performed well is provided. New decomposition methods are proposed and several of these methods are shown to attain better performance than previously known methods of decomposition. The convergence of various degrees of multi-objectivization is examined leading to a new, more general segmentation algorithm, Multi-Objectivization via Progressive Segmentation (MOPS). MOPS combines the single-objective genetic algorithm with multi-objectivization in a general form. In a given run MOPS can progress from a more traditional single objective method to a strong multi-objectivization method. MOPS attempts to improve the ratio of fitness improvements to fitness decrements, signal-to-noise ratio (SNR), over the course of an evolutionary optimization based on the principle that often fitness improvements are generally easier to find early in the run rather than late in the run. It is shown that MOPS provides robust performance across a variety of problem instances and different computational budgets. 相似文献
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A fast and accurate characterization method of differential via holes is presented based on the equivalent circuit extraction technique. A 3‐D model of differential via holes is created and simulated using a full wave solver and the results are compared with the equivalent circuit model using Advanced Design System software. Results presented validate the proposed approach. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007. 相似文献
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陈小芳 《数字社区&智能家居》2014,(1):51-53,66
RMI是开发Java网络分布式应用系统的一个重要框架,开发人员通过运用RMI框架将更易于分布式系统的开发。该文详细介绍了RMI的运行机制,并对运用RMI框架进行分布式系统的开发步骤进行了阐述,最后给出了RMI技术的具体应用实例和实现方法。 相似文献
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In this paper gas-kinetic BGK scheme is applied to simulate 2-D supersonic mixing layer with free-stream Mach numbers ranging from 1.1 to 1.9 on one side and 2.3 to 3.1 on the other. The convective Mach number Mc falls in the range 0.2–1.0. The numerical results provide the flow-field structure, the characteristic of velocity fluctuation, the self-similarity profiles of the mean velocity, Reynolds stresses and high-order moments of velocity fluctuation. The mean velocity field and the normalized growth rate agree well with experimental results. Due to 2-D limitations the velocity fluctuation intensities and shear stress are overpredicted, especially in cases with high Mc. The pairings of large structures in high Mc mixing layers still exist, although compressibility restrains their development. Present study reveals the good property of the BGK scheme in the simulation of compressible flows that ensures its wide applications. 相似文献