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电能质量干扰发生装置的研制 总被引:1,自引:0,他引:1
电能质量干扰发生器常用于检验电力设备受电能扰动时的性能,提出了一种基于波形信号发生器加线性功率放大器的电能质量干扰发生器装置的设计方案.以可编程逻辑器件EPM7128、双口RAM和数模转换器为基础,采用直接数字合成技术设计了正弦信号产生电路.利用SM5964单片机对数模转换器的参考电压进行控制来改变波形输出幅度,实现小信号的聚升、跌落、中断和凹陷等功能.通过高压高速集成功率运放PA89A对小信号进行幅度放大,采用高压高频三极管并联技术设计了扩流电路.使用Multisim软件对功率放大电路的参数进行仿真和优化,仿真实验结果表明,该电能干扰发生装置的输出电压幅值在0 ~264 V范围内任意可调,负载电流达到2A,并能实现电压跌落、聚升、中断和凹陷等功能. 相似文献
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阐述了采用数模混合技术完成交流激磁电源的设计方法,利用数字技术产生稳定正弦波信号,经低通滤波、功率放大生成具有一定驱动能力的交流信号,并对输出信号进行闭环控制,以达到稳幅的目的;主要描述了供电电路、交流功率驱动电路、闭环控制电路的设计方法;通过本设计方法,可以产生在宽温度范围、多负载情况下产生稳频稳幅的交流传感器激磁电源;并通过温度试验、带负载能力试验、输出短路试验验证了该交流激磁电源的频率稳定性和幅值稳定性,以及输出短路时的自保护能力。 相似文献
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基于FPGA的DDS信号发生器设计 总被引:1,自引:0,他引:1
设计了一种可灵活在线调节的直接数字频率合成信号发生器,首先利用现场可编程门阵列生成各种频率、波形的信号数据,再采用LTC1821实现D/A转换,最后通过选择性滤波和功率放大电路实现信号输出,幅值范围0~10V,频率范围1Hz~100kHz,波形可设为三角波、矩形波、正弦波、锯齿波;实际测试验证了信号发生器的准确性和有效性. 相似文献
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基于FPGA高速数据采集的电化学阻抗分析仪的研制 总被引:3,自引:2,他引:1
以FPGA、C8051f单片机及高速AD/DA转换器、DDS信号发生器、频率响应分析器配合恒电位仪,设计一套包括正弦波输出、高速数据采集、实时图形显示的电化学阻抗测试系统.系统采用数字相关算法来测量电压与电流信号的相位差和幅值,提高测试精度,通过双通道信号积分和自动去偏置电路,极大地提高信噪比.通过试验发现,所设计的仪器与国外同类型仪器的测量结果几乎一致.并较后者具有更宽的频率分析范围. 相似文献
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CCD相机功率驱动电路设计 总被引:1,自引:0,他引:1
由于一些CCD的驱动波形为双极性且电压幅值范围较宽,而目前的CCD驱动集成电路多为单电源工作且工作电压幅值有时候不能满足要求。针对这个问题,设计了新的CCD相机的功率驱动电路。该功率驱动电路采用电容耦合及二极管钳位方式对时序信号进行电平搬移,采用两个互补三极管轮流开关工作产生驱动波形。由于采用了较少的器件,提高了电路的可靠性,降低了系统的成本。对电路进行了分析,并在Cadence公司的OrCAD PSpice AD软件下进行了仿真。构建实际的电路和仿真结果一致。因此,当现有的驱动器集成电路不能满足要求时,可以使用该电路实现CCD相机的功率驱动。 相似文献
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由于低射速大口径火炮的弹丸口径较大,目前的感应装定系统无法实现无线能量的远距离传输。为了解决这一问题,在传统装定器电路中引入射频识别(RFID)技术中的功率放大电路,将调制信号先进行放大再加载到发射线圈上,即可得到较大的输出信号,实现远距离传输。所设计的功放电路的载波频率为1 MHz。通过Multisim 10.0仿真软件,构建了D类功率放大电路。对放大器的相关性能进行仿真测试,从而得到合适的电路元件参数。搭建了试验平台,通过解调电路测试发现,在电源电压为15 V时,最远感应装定距离可以达到12 cm,解码电路也可以得到完整的原始信号,完全满足火炮装定时的最小距离要求。随着电源电压的升高,感应装定距离也在变大,保证了信号和能量的远距离传输。 相似文献
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S. Shaw 《Journal of Computer Assisted Learning》1993,9(2):93-99
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained. 相似文献
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European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven. 相似文献
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融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。 相似文献
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Wayne O’Brien Author Vitae 《Journal of Systems and Software》2008,81(11):1997-2013
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them. 相似文献
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This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives. 相似文献
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Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what
is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic
sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and
its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of
an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify
robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can
or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
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David Poole 《Computational Intelligence》1989,5(2):97-110
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given. 相似文献
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Watts S. Humphrey 《Annals of Software Engineering》2002,14(1-4):39-72
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical. 相似文献
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基于复小波噪声方差显著修正的SAR图像去噪 总被引:4,自引:1,他引:3
提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。 相似文献