共查询到20条相似文献，搜索用时 515 毫秒
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《实验室研究与探索》2017,(7)
为了提高频率计的测量精度和系统性能,解决在传统的频率计中无法实现高低频率等精度测量的情况,采用京微雅格公司的M7系列FPGA,设计了一种基于SOPC技术的等精度多功能频率计。该频率计以内嵌Cortex-M3内核的FPGA芯片为控制核心,通过对FPGA模块和Cortex-M3内核部分的设计,并借助AHB接口的FIFO实现FPGA与Cortex-M3内核之间的数据通信,完成了1Hz~50MHz范围内等精度频率计的设计。通过Model Sim软件仿真和硬件实测表明,该频率计可以完成等精度频率和占空比的测量功能,具有精度高、实时性好等特点。 相似文献
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郭豫荣 《赤峰学院学报(自然科学版)》2012,(16):73-74
频率计的测量精度随着被测量信号频率的降低而下降,而等精度频率计既具有较高的测量精度,又能在整个频率范围内保持恒定的精度.本论文采用EDA技术结合硬件描述语言VHDL对频率计系统进行设计,分析了等精度频率计测量频率的原理,给出了其硬件设计方案及实验结果. 相似文献
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饶成明 《希望月报(上半月)》2008,(3):23-25
在对三种测频方法进行分析的基础上,介绍了基于EDA技术的等精度测频原理.给出采用AT89C51实现控制并通过FPGA来设计多功能等精度数字频率计的具体方法.该频率计可以兼顾频率计对速度、资源和测频精度等各方面的优化需求. 相似文献
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孙健 《贵阳学院学报(自然科学版)》2007,2(3):29-32
基于传统的频率计设计复杂、操作繁琐的问题,提出了一种基于单片机的简单可靠、小型化频率计的设计方法.这种单片机的使用,使得频率计的电路更加简单可靠,而且电路完成功能的精度更高. 相似文献
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文章根据电子设计自动化中频率计的计频原理,结合一些具体的仿真波形,介绍了提高频率计精度的方法,通过完善使得电路计算出的频率值更为精确且易于理解.进而介绍拓展可测信号频率的范围的方法.扩大了频率计的应用范围. 相似文献
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运用VHDL在FPGA/CPLD器件上实现一种数字频率计测频系统,分析了数字频率计软件构成结构,并对其中的测频控制信号发生器电路进行了VHDL软件编程实现。 相似文献
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运用VHDL在FPGA/CPLD器件上实现一种数字频率计测频系统,分析了数字频率计软件构成结构,并对其中的测频控制信号发生器电路进行了VHDL软件编程实现。 相似文献
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江军强 《内江师范学院学报》2010,25(4):50-53
主要论述了成绩查询系统的分析、设计和实现,具体介绍了成绩查询、成绩下载、成绩统计等三个功能模块的程序流程图和主要程序代码．本系统基于ACCESS数据库、采用ASP技术开发实现．该系统既能实现一般的考生成绩查询功能,又能面向教师实现班级成绩查询、下载、统计功能．本系统在实际当中投人运行,经过不断修正,实现了预期的功能． 相似文献
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The National Assessment Program – Literacy and Numeracy (NAPLAN) is a nationwide testing program for literacy and numeracy in Australia. Several studies explored and used NAPLAN numeracy test results as a source of valuable data and a potential means to improve education. This paper presents a systematic literature review to investigate the use of NAPLAN numeracy test results in those peer-reviewed articles in relation to the purposes of NAPLAN results mentioned by the Australian Curriculum, Assessment and Reporting Authority (ACARA). Findings showed a variety of uses of the NAPLAN numeracy test results in these studies. Most of the studies used the test results to map student progress and identify strengths and weaknesses in teaching. A significant number of studies used the NAPLAN numeracy test results that differ from the purposes mentioned by ACARA. The review concluded that there is currently insufficient use which reflects the purpose of NAPLAN test results. 相似文献
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苑玉成 《唐山师范学院学报》2001,23(4):43-46,56
创新既有语词意义，又有概念意义，熊彼特的创新理论主要指技术创新和管理创新，是经济学中的概念，根据创新的广阔性，不能把创新仅限于经济学范围之内，凡是在已知信息的基础上，经过思维活动或者实施行为能产生有价值的新成果的活动都是创新。创新成果分为观念成果和再造成果。发明、发现、创造都是创新，但它们取得的成果是观念成果，是不完全创新。不完全创新有科学价值，但对人类社会没有实际贡献。完全创新是将观念成果继续推进，纳入实施轨道，从而产生再造成果并争得经济效益和社会效益的综合活动。 相似文献
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研究了Hilbert空间中一类强伪压缩映射的不动点问题,提出了一个新的路径公式,得到了一个新的不动点存在定理和路径收敛性结果.给出了所得结果在变分不等式解存在性研究中的应用. 相似文献
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Chris Ricketts 《Assessment & Evaluation in Higher Education》2010,35(4):351-356
The article challenges common practice in relation to resits of ignoring the main assessment results and making high‐stakes decisions on the basis of resit results alone. Implications for institutions, students and educators are discussed. The proposal is that not all resits should be treated equally and that, in some circumstances, more robust decisions can be made by combining resit results with the results from the main assessment. 相似文献
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Although much research has been conducted on the psychometric properties of cognitive diagnostic models, they are only recently being used in operational settings to provide results to examinees and other stakeholders. Using this newer class of models in practice comes with a fresh challenge for diagnostic assessment developers: effectively reporting results and supporting end users to accurately interpret results. Achieving the goal of communicating results in a way that leads users of the assessment to make accurate interpretations requires a prerequisite step that cannot be taken for granted. The assessment developers must first accurately interpret results from a psychometric, or measurement, standpoint. Through this article, we seek to begin a discussion about reasonable interpretations of the results that classification‐based models provide about examinees. Interpretations from published research and ongoing practice show different—and sometimes conflicting—ways to interpret these results. This article seeks to formalize a comparison, critique, and discussion among the interpretations. Before beginning this discussion, we first present background on the results provided by classification‐based models regarding the examinees. We then structure our discussion around key questions an assessment development team needs to answer themselves prior to constructing reports and interpretative guides for end users of the assessment. 相似文献
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《International Journal of Educational Research》2001,35(4):373-389
This chapter presents and discusses the results of the study. The results are presented in three sections: results of the correlational analysis, results of the regression analysis, and results of the path analysis. In general the results suggest that family background is indirectly linked to GPA by virtue of its direct effect on study behaviors, verbal ability, and nonverbal ability. Similarly, the link between study behaviors and GPA is mediated through verbal ability and nonverbal ability. Family background and study behaviours consistently predicted nonverbal ability, verbal ability, and GPA, even after the effects of the other cognitive variables had been removed. 相似文献