期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
电子通讯设备的ESD防护设计
1
作者 范大祥 《质量与可靠性》 2002年第5期21-24,共4页
简要介绍了ESD的损伤模型和ESD对于电子通讯设备的危害,并从PCB的ESD防护设计、金属部件和金属外壳接插件的ESD防护设计、机壳的ESD防护设计和采用ESD防护的元器件四个方面详细讨论了电子通讯设备ESD防护设计的方法。
关键词 电子通讯设备 防护设计 静电放电 静电屏蔽 滤波去耦 绝缘隔离
下载PDF
Coupling denoising algorithm based on discrete wavelet transform and modified median filter for medical image 被引量:27
2
作者 CHEN Bing-quan CUI Jin-ge +2 位作者 XU Qing SHU Ting LIU Hong-li 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第1期120-131,共12页
In order to overcome the phenomenon of image blur and edge loss in the process of collecting and transmitting medical image,a denoising method of medical image based on discrete wavelet transform(DWT)and modified medi... In order to overcome the phenomenon of image blur and edge loss in the process of collecting and transmitting medical image,a denoising method of medical image based on discrete wavelet transform(DWT)and modified median filter for medical image coupling denoising is proposed.The method is composed of four modules:image acquisition,image storage,image processing and image reconstruction.Image acquisition gets the medical image that contains Gaussian noise and impulse noise.Image storage includes the preservation of data and parameters of the original image and processed image.In the third module,the medical image is decomposed as four sub bands(LL,HL,LH,HH)by wavelet decomposition,where LL is low frequency,LH,HL,HH are respective for horizontal,vertical and in the diagonal line high frequency component.Using improved wavelet threshold to process high frequency coefficients and retain low frequency coefficients,the modified median filtering is performed on three high frequency sub bands after wavelet threshold processing.The last module is image reconstruction,which means getting the image after denoising by wavelet reconstruction.The advantage of this method is combining the advantages of median filter and wavelet to make the denoising effect better,not a simple combination of the two previous methods.With DWT and improved median filter coefficients coupling denoising,it is highly practical for high-precision medical images containing complex noises.The experimental results of proposed algorithm are compared with the results of median filter,wavelet transform,contourlet and DT-CWT,etc.According to visual evaluation index PSNR and SNR and Canny edge detection,in low noise images,PSNR and SNR increase by 10%–15%;in high noise images,PSNR and SNR increase by 2%–6%.The experimental results of the proposed algorithm achieved better acceptable results compared with other methods,which provides an important method for the diagnosis of medical condition. 展开更多
关键词 medical image image denoising discrete wavelet transform modified median filter coupling denoising
下载PDF
Design of decoupling Smith control for multivariable system with time delays 被引量:1
3
作者 黄灿 桂卫华 +1 位作者 阳春华 谢永芳 《Journal of Central South University》 SCIE EI CAS 2011年第2期473-478,共6页
In order to solve the decoupling control problem of multivariable system with time delays,a new decoupling Smith control method for multivariable system with time delays was proposed. Firstly,the decoupler based on th... In order to solve the decoupling control problem of multivariable system with time delays,a new decoupling Smith control method for multivariable system with time delays was proposed. Firstly,the decoupler based on the adjoint matrix of the multivariable system model with time delays was introduced,and the decoupled models were reduced to first-order plus time delay models by analyzing the amplitude-frequency and phase-frequency characteristics. Secondly,according to the closed-loop characteristic equation of Smith predictor structure,proportion integration (PI) controllers were designed following the principle of pole assignment for Butterworth filter. Finally,using small-gain theorem and Nyquist stability criterion,sufficient and necessary conditions for robust stability were analyzed with multiplicative uncertainties,which could be encountered frequently in practice. The result shows that the method proposed has superiority for response speed and load disturbance rejection performance. 展开更多
关键词 multivariable process time delay Smith predictor DECOUPLING robust stability
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部