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李乐 《数字社区&智能家居》2011,(13)
根据基带传输相关课程内容的特点,提出采用MATLAB/Simulink仿真来进行演示和实验以解决相关的问题。同时阐述了使用MATLAB/Simulink对基带传输系统仿真的过程。 相似文献
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Karun Rawat Fadhel M. Ghannouchi Meenakshi Rawat Mohammad S. Hashmi 《国际射频与微波计算机辅助工程杂志》2011,21(3):325-335
This article proposes an analytical design methodology for dual‐band hybrid couplers and baluns structures for any arbitrary frequency ratio using a stub‐loaded transmission line. An analysis of changing the impedance behavior of the stub, is carried out for the two bands of operation, which along with a dispersive analysis, emphasizes certain conditions where the existing methodology is not applicable. In addition, an extra degree of freedom has been included to increase the solutions for a given frequency ratio, thus providing greater flexibility and feasibility of the proposed structure. The design methodology is experimentally validated with the design and fabrication of dual‐band branch‐line and rat‐race couplers for various commercial frequency bands. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2011. 相似文献
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Potential phase diagrams, where the chemical potential of a compound is used as an axis, do not obey the usual rules for potential phase diagrams. Examples are presented in order to help the interpretation of such diagrams. The thermodynamic background of the special properties is examined. 相似文献
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Yi-Yan Liu Yong-Feng JuChen-Dong Duan Xue-Feng Zhao 《Engineering Applications of Artificial Intelligence》2011,24(1):87-92
A structure damage diagnosis method combining the wavelet packet decomposition, multi-sensor feature fusion theory and neural network pattern classification was presented. Firstly, vibration signals gathered from sensors were decomposed using orthogonal wavelet. Secondly, the relative energy of decomposed frequency band was calculated. Thirdly, the input feature vectors of neural network classifier were built by fusing wavelet packet relative energy distribution of these sensors. Finally, with the trained classifier, damage diagnosis and assessment was realized. The result indicates that, a much more precise and reliable diagnosis information is obtained and the diagnosis accuracy is improved as well. 相似文献
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A novel square ring printed antenna has been suggested for dual‐band circular polarization (CP). The geometry contains a square patch and a square ring structure for dual‐band operation. Circular polarization is achieved using triangular cut at the boundary and right angle bend with inner perturbation. The suggested antenna is excited from the lower layer through electromagnetic (EM) coupling technique. The antenna shows good impedance bandwidths of 90 MHz (2.43‐2.52 GHz) and 800 MHz (5.7‐6.5 GHz, respectively. The antenna shows 3 dB axial ratio bandwidth of 20 MHz at lower band and 120 MHz at upper band with improved gain > 6 dBi. The simulated and measured results are well agreed with each other. The antenna is promising wideband operation at the upper band. This antenna was implemented on fiberglass reinforcement laminated Arlon substrate with dielectric constant (?r = 2.55), and the overall physical dimension of 30 × 30 × 3.048 mm3. The designed antenna can be extensibly applicable in WLAN/Wi‐MAX communication. The presented antenna is designed using hyperlynx IE3D and the simulated results are presented. 相似文献