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1.
本文借助MALABGUI实现了<信号与系统>课程中信号频谱分析系统,该系统可实现连续周期、连续非周期、离散周期、离散非周期等四类常见信号的频谱分析,通过键盘或鼠标能够很方便的修改信号时域的参数,并能实时的显示频域的对应变化趋势;通过具体实例对系绫各模块进行了说明.将该系统和教学实验结合,取得了良好的效果.  相似文献   

2.
本文设计了一种基于D S P的数据采集系统。该系统以TI公司的浮点DSP芯片TMS320F28335作为信号采集和处理的核心,用FFT技术对信号进行频谱分析。上位机利用VC6.0软件平台加入TeeChart控件,在该平台上实现信号波形显示与分析。  相似文献   

3.
用FFT测量音频信号失真度的误差研究   总被引:4,自引:0,他引:4  
陆慧娟 《科技通报》1998,14(4):270-275
应用快速傅里叶变换(FFT)算法对频谱进行分析,从而实现在计算机中对音频信号失真度的直接测量.本文还着重分析了失真度误差的来源,并在大量实验的基础上,提出了相应的解决办法——运用加汉宁窗口和整个主瓣宽度作为基波值来减少FFT引起的误差  相似文献   

4.
本系统利用DFT法对音频信号进行频谱分析,应用S3C44B0X芯片作为系统的核心,再配以采样保持、程控放大等功能模块,构成了一个音频信号分析仪。频谱测量频率范围为100Hz-10KHz,频谱分辨率达到20HZ。  相似文献   

5.
本文介绍了基于集成混合信号处理器ADuC7026和FFT技术的便携式音频信号分析仪的设计。系统采用了增益可编程放大器CS3310构成的模拟前端,可满足输入信号动态范围大的要求。音频信号由ADuC7026测量与分析,功率、失真度、频谱结构等指标在LCD上显示。系统电路简单,稳定性好,具有较高的性能价格比。  相似文献   

6.
文章针对传统信号分解原理解析实验方法的不足,设计了一种新型的FPGA可编程器件的可视化的信号分解原理解析实验系统,首先对输入复杂信号分解,提取各次谐波,其次将输入复杂信号和输入信号的频谱、各次谐波信号、各次谐波频谱实时同步显示在一个液晶显示器上。达到准确地理解复杂周期信号的傅里叶分解的过程和原理的目的,避免抽象的数学分析,极大提升教学效果和学生的学习兴趣。  相似文献   

7.
在实际工程应用中,为了校准振动传感器的输出精度并检验其输出幅频特性,利用Lab VIEW软件及其DAQmx驱动开发一套能够采集多路振动传感器的输出幅值和频谱分析的实时数据采集系统,同时能够存储相关数据以便事后进行回放分析。通过对多路振动传感器的幅值采样、数据存储、波形显示及信号的频谱分析等工作,可对传感器进行更好的校准工作。  相似文献   

8.
信号的频谱分析是信号与系统分析的基础。文章分析了用数值计算的方法实现确知连续时间信号的频谱分析,即采用离散傅里叶变换的快速算法实现对连续信号的频谱估计,然后在MATLAB语言工具下结合正弦信号给出了频谱分析的结果。  相似文献   

9.
刘琦 《内江科技》2006,27(4):87-87
本文做出一种用matlab系统实现由自相关函数求信号频谱的方法。通过matlab实现对信号自相关函数的估计,较为方便的求出信号的频谱。  相似文献   

10.
本文详细说明了快速傅里叶变换(FFT)的原理,借助蝶形图总结出码位倒序和蝶形运算的规律,推导得FFT算法。将其用C语言实现并在STM32上运行,调用LCD库函数在LCD屏幕上显示出给定信号的频谱图。用matlab仿真验证,对比发现仿真得到的频谱图与本系统所得频谱图完全一致,说明了本系统设计的正确性。  相似文献   

11.
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.  相似文献   

12.
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.  相似文献   

13.
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.  相似文献   

14.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.  相似文献   

15.
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.  相似文献   

16.
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.  相似文献   

17.
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.  相似文献   

18.
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence  相似文献   

19.
<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese  相似文献   

20.
<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.  相似文献   

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