Thirteenth National Radio Science Conference. NRSC '96最新文献_第5页

Elimination of backscattering from conducting surfaces using externally loaded straight wire system 利用外负载直线系统消除导电表面的后向散射

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551109

S. Zainud-Deen

引用次数: 1

A novel built-in-self test structure for analog circuits with application to filters 一种适用于滤波器的模拟电路内置自检结构

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551128

F. Amer

引用次数: 0

Challenges in modern wireless personal communications 现代无线个人通信面临的挑战

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551098

S. El-Ghazaly, M. Golio

引用次数: 0

Time-dependence of backscattered intensities of a sphere illuminated with very short electromagnetic pulses 极短电磁脉冲照射球面后向散射强度的时间依赖性

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551108

E. Khaled

{"title":"Time-dependence of backscattered intensities of a sphere illuminated with very short electromagnetic pulses","authors":"E. Khaled","doi":"10.1109/NRSC.1996.551108","DOIUrl":"https://doi.org/10.1109/NRSC.1996.551108","url":null,"abstract":"Scattered time-dependent intensities from a dielectric sphere illuminated with a very short pulsed plane wave are calculated. The time dependence of the incident pulse is considered to be a rectangular or a Gaussian function. The results are obtained for a sphere on a resonant mode. The frequency spectrum of the scattered field at a point is calculated using the incident field spectrum and the transfer function at that point. The transfer function at any frequency of the sphere at a space point is calculated using the T-matrix method. The inverse Fourier transform of the frequency spectrum is used to calculate the time-dependence of the scattered electric field. The scattered intensities are calculated for pulses of durations (/spl sim/10 ps) smaller than the resonant lifetime. The computer codes are capable of calculating the scattered intensity of a shorter pulse. The computations for such shorter pulses depend on the capacity and speed of the computer system. The main factors which affect the behavior of the scattered pulse are the incident pulse spectrum (or duration) and the lifetime of the resonant mode of the sphere.","PeriodicalId":127585,"journal":{"name":"Thirteenth National Radio Science Conference. NRSC '96","volume":"362 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115552880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Neural matched filter detection in synchronous code-division multiple-access (CDMA) systems 同步码分多址(CDMA)系统中的神经匹配滤波器检测

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551117

S. El-Khamy, H. Abdou

{"title":"Neural matched filter detection in synchronous code-division multiple-access (CDMA) systems","authors":"S. El-Khamy, H. Abdou","doi":"10.1109/NRSC.1996.551117","DOIUrl":"https://doi.org/10.1109/NRSC.1996.551117","url":null,"abstract":"In communication networks employing spread-spectrum (SS) code-division multiple-access (CDMA), the performance of single user matched filter receivers are highly degraded when the relative powers of the interfering signals are large (the near-far problem). Optimum multiuser (maximum likelihood) receivers have been suggested to overcome the near-far problem, but they are too complex to implement, specially when the number of users is high. In addition, such multiuser detectors lacks security, which is one of the main advantages of SS techniques, as all of the users messages are detected simultaneously. We introduce a new technique for separately demodulating the packets belonging to different users using feedforward artificial neural networks. A special neural network, the neural matched filter (NMF), is trained not only to detect the spreading code of the assigned user but also to suppress the multiple-access interference caused by the waveforms of other users. This technique is shown to be highly resistant to near-far effects. A comparative performance analysis of conventional, optimum multiuser and NMF single user receivers is carried out via Monte Carlo simulation. It is shown that the proposed single user NMF detectors have a better performance than the optimum receiver in severe near-far cases. This exalted performance is due to the implicit cancellation of cross-correlation between different users codes. The suggested technique is also not sensitive to the code selection and does not necessitates the use of sophisticated optimized code families. Our suggested NMF technique solves most of the security, complexity and near-field problems associated with CDMA systems.","PeriodicalId":127585,"journal":{"name":"Thirteenth National Radio Science Conference. NRSC '96","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130185667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Online multilevel controller structure for a class of dynamical systems 一类动态系统的在线多电平控制器结构

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551129

G. Z. El-Far, M. Nassef, A. Montasser

引用次数: 0

Analysis and synthesis of multiple-focus phased array heating patterns through the rib cage: a simulation model 通过胸腔的多焦点相控阵加热模式的分析与合成:一个仿真模型

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551096

Y. Botros, J. Volakis, E. Ebbini

引用次数: 4

Direction of arrival estimation techniques using uniform circular array 均匀圆阵到达方向估计技术

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551102

M. Mokhtar, M. A. Kader, M. Kassem

引用次数: 1

Design of neural networks for solving computational problems 解决计算问题的神经网络设计

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551119

H. El-Bakry, M. Abo-Elsoud, H. Soliman, H. El-Mikati

引用次数: 0

Time domain modelling of microwave systems and subsystems 微波系统和子系统的时域建模

Thirteenth National Radio Science Conference. NRSC '96 Pub Date : 1996-03-19 DOI: 10.1109/NRSC.1996.551125

M. Sobhy, E. A. Hosny, M. Ng, E.A. Bakkar

引用次数: 0