Proceedings of the Nineteenth National Radio Science Conference最新文献_第4页

The MVDR guided constant modulus adaptive array (MVDR-GCMARY) for signal separation in fading channels MVDR制导恒模自适应阵列(MVDR- gcmary)用于衰落信道中的信号分离

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022615

S. El-Khamy, D. Abd-Elaziz, A.M. Gab-Alla

{"title":"The MVDR guided constant modulus adaptive array (MVDR-GCMARY) for signal separation in fading channels","authors":"S. El-Khamy, D. Abd-Elaziz, A.M. Gab-Alla","doi":"10.1109/NRSC.2002.1022615","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022615","url":null,"abstract":"The constant modulus array (CMARY) is a blind adaptive beamformer, which is capable of recovering a narrowband signal that is received along with other cochannel signals without using a pilot or training signal. It is based on the constant modulus algorithm (CMA) The CMARY typically captures the signal that has the greatest power among the cochannel signals received by the array. In order to help the beamformer select-the desired signal, the capture process should be controlled, or guided, by controlling the initial weights of the array. This can be done by using a suitable method for direction of arrival (DOA) estimation, such as subspace-based methods, e.g. the MUSIC algorithm, to estimate the angle of arrival of the desired signal. The initial weights of the array are then computed using a suitable beamforming technique such as MVDR to recover the desired signal. By this way the desired signal will have a dominant power at the array output and the CMARY array will capture the desired signal. The resulting configuration is named the MVDR guided constant modulus array (MVDR-GCMARY) and is described in detail in this paper. Computer simulations show the high efficiency of the proposed GCMARY in separating cochannel signals received from different sources and directions for different scenarios of signal constellations, array geometries and channel fading and multipath characteristics.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132610989","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: 8

Modeling transconductance- and capacitance-voltage characteristics of AlGaAs/GaAs HEMTs 模拟AlGaAs/GaAs hemt的跨导和电容电压特性

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022657

R. Abdelrassoul, M. Yakout, A. AbdelFattah, S.G. Essa

引用次数: 1

Radio science on the Cassini mission to Saturn 卡西尼号土星任务的无线电科学

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022603

E. Marouf

引用次数: 3

Heart diseases diagnosis using heart sounds 利用心音诊断心脏病

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022675

O. Abdel-Alim, N. Hamdy, M. El-Hanjouri

引用次数: 21

Pseudo-exact simple closed-form solutions for radiation and scattering from thin straight loaded and unloaded wires 细直载和无载导线辐射和散射的拟精确简单封闭解

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022612

M. Fahmy, I. Eshrah

{"title":"Pseudo-exact simple closed-form solutions for radiation and scattering from thin straight loaded and unloaded wires","authors":"M. Fahmy, I. Eshrah","doi":"10.1109/NRSC.2002.1022612","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022612","url":null,"abstract":"A 'fictitious' hypothetical transmission line model is introduced and proved to be extremely useful in the determination of current distribution on thin straight loaded and unloaded wire antennas or scatterers. Thus, all problems of straight wire radiators and scatterers are simply treated in terms of simple transmission line conceptions, yielding simple closed-form solutions. Surprisingly enough, the obtained solutions showed remarkable agreement with the sophisticated moment method solutions except for particular lengths. Besides the expected huge saving in computation time, as compared with moment method solutions, the newly obtained simple closed-form solutions revealed, as well, a simple elegant physical picture of current distribution on straight wire scatterers. Thus while pseudo-exact antenna current distribution comprises one simple standing wave with complex propagation constant, the pseudo-exact current distribution on the unloaded scatterer comprises just two standing waves with complex propagation constant too, besides a third term having direct correspondence to the incident excitation.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127002993","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: 7

Information theoretic unified modelling of autonomous systems 自治系统的信息论统一建模

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022605

E. Badreddin

引用次数: 0

Neural networks used for speech recognition 用于语音识别的神经网络

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022622

S. El-Ramly, N. Abdel-Kader, R. El-Adawi

{"title":"Neural networks used for speech recognition","authors":"S. El-Ramly, N. Abdel-Kader, R. El-Adawi","doi":"10.1109/NRSC.2002.1022622","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022622","url":null,"abstract":"Neural networks are applied to the recognition of Arabic phonemes. Time delay neural networks (TDNN) have been chosen for the problem of Arabic speech recognition because of their ability to represent relationships between acoustic events. Two Arabic categories have been chosen, nasals and voiced stops, to evaluate the performance of TDNN in Arabic speech recognition. The effect of several factors on the recognition rate have been studied: (i) the length of the analysis frame (10 ms and 20 ms); (ii) truncating or zero padding the signal versus re-sampling the signal to obtain a signal of fixed length; (iii) using a single neural network versus a separate neural network for each phoneme category; and (iv) the size of the TDNN. The length of the 20 ms analysis frame obtained higher recognition rates than the 10 ms frames. Truncating or zero padding the signal to obtain a fixed length signal gave higher recognition rates than re-sampling the signal. A 9% increase for nasals and 2.4% increase for stops, were obtained when using a separate TDNN for each phoneme category. It was also found that the size of the network depends on the complexity of the recognition problem.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124053868","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: 24

Low-power CMOS analog front-end for wireless communication 低功耗CMOS模拟前端无线通信

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022656

A. Taha, M.A. Abo-El-Soud, R. Abdelrassoul, A. Farrag

引用次数: 1

Use of active phased arrays for multiple-beam cellular communications systems 多波束蜂窝通信系统中有源相控阵的使用

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022601

A. Zaghloul, O. Kilic

{"title":"Use of active phased arrays for multiple-beam cellular communications systems","authors":"A. Zaghloul, O. Kilic","doi":"10.1109/NRSC.2002.1022601","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022601","url":null,"abstract":"Active phased array antennas offer an efficient and more versatile alternative to reflector antennas for use in communications systems that require multiple beams. The use of such antennas is evident in newly developed satellite communications systems and in base stations for wireless systems. The advances in monolithic microwave integrated circuits (MMIC) and digital technologies played a major role in realizing these arrays for satellite applications. However, the added requirements and active array characteristics introduce a set of transmission impairments in the communications link that did not necessarily exist in the conventional systems. This paper reviews phased array developments for multiple-beam cellular communications applications. The paper describes hardware designs to meet coverage requirements. These include the modular MMIC beam-forming matrices that generate a number of simultaneous and independent beams that are controlled digitally. The communications link and system aspects of the active phased array are assessed through measurements and analysis. Three link parameters are investigated and their effects on the overall carrier-to-interference ratio are quantified. The first parameter is the intermodulation components that are generated at the non-linear amplifier outputs and contribute to well-formed interference in the far field radiation of the array. The second is the bit-error ratio (BER) degradation due to the multi-carrier operation of the active array. Measurement results are shown to demonstrate this effect. The third link parameter is the co-channel interference caused by frequency re-use in multiple beam systems. Antenna performance for both user terminals and satellite payload (or cellular system base station) as well as coverage requirements and user traffic within each beam contribute to this interference effect.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126032925","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

An efficient object tracking technique using block-matching algorithm 基于块匹配算法的高效目标跟踪技术

Proceedings of the Nineteenth National Radio Science Conference Pub Date : 2002-11-07 DOI: 10.1109/NRSC.2002.1022651

S. A. El-Azim, I. Ismail, H.A. El-Latiff

引用次数: 25