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Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)最新文献

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Spatial correlation function of the sky wave for use in space diversity reception 用于空间分集接收的天波空间相关函数
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760943
A. Ghuniem, N. Osman
{"title":"Spatial correlation function of the sky wave for use in space diversity reception","authors":"A. Ghuniem, N. Osman","doi":"10.1109/NRSC.1999.760943","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760943","url":null,"abstract":"Fading is a serious problem in HF communication. It is caused primarily by the random irregularities in the refractive index of the ionosphere. One of the successful solutions to this problem is the space diversity reception. In this work the spatial correlation function of the received signal fluctuations is derived using geometric optics and single scattering approximations. Then the correlation function is used to calculate the required distance between the two receiving antennas to obtain uncorrelated signals. The results provide the base for the optimum design of the space diversity system.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127012885","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
Beam profile of a parallel plane electrodes focusing system 平行平面电极聚焦系统的光束轮廓
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760949
F. Salam, O. Moustafa, H. El-Khabeary T.
{"title":"Beam profile of a parallel plane electrodes focusing system","authors":"F. Salam, O. Moustafa, H. El-Khabeary T.","doi":"10.1109/NRSC.1999.760949","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760949","url":null,"abstract":"The present work investigates the potential distribution in a five electrode lens to be used in an electrostatic ion source. The beam profile shape has been investigated using different gases. The radii of the beam profile along the axial distance using N/sub 2/ gas are calculated for different perveances, different initial beam radii, different ion charges, and different ratios of voltage magnitude. It has been found that a minimum beam radius of 0.22 mm can be obtained for initial beam radius equal 2.5 mm using N/sub 2/ gas. The present lens constitutes a convergent lens. It gives a more focused beam than the case of two hemispherical electrodes and an intermediate flat electrode.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125660631","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
Wave excitation by REB in a waveguide filled with warm, magnetized plasma REB在充满温暖磁化等离子体的波导中激发波
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760940
S. Khalil, K. El-Shorbagy, E. N. El-Siragy
{"title":"Wave excitation by REB in a waveguide filled with warm, magnetized plasma","authors":"S. Khalil, K. El-Shorbagy, E. N. El-Siragy","doi":"10.1109/NRSC.1999.760940","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760940","url":null,"abstract":"An important application of a relativistic electron beam (REB) is investigated, i.e., minimizing the energy losses in a waveguide filled with a warm, magnetized plasma. An analytical calculation is performed to find the plasma dielectric constant, which leads one to apply the boundary conditions at the plasma conductor interface. The dispersion equations which describes the electromagnetic waves, hence their damping rate in the waveguide, are derived. The necessary condition for the field stability and the amplification coefficient of these waves are obtained. The electron beam is found to play a crucial role in the field stability and in controlling the field attenuation in the waveguide.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130821597","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: 2
Performance analysis of QPSK and 16-ary PSK systems in a land mobile regenerative satellite link 陆地移动再生卫星链路中QPSK和16元PSK系统的性能分析
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760906
S. El-Agaoz, G. Mabrouk, E. Eweda
{"title":"Performance analysis of QPSK and 16-ary PSK systems in a land mobile regenerative satellite link","authors":"S. El-Agaoz, G. Mabrouk, E. Eweda","doi":"10.1109/NRSC.1999.760906","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760906","url":null,"abstract":"An analytical technique is developed to evaluate the error rate performance of quadrature phase shift keying (QPSK) and 16-ary phase shift keying (16-ary PSK) in a land mobile satellite communication channel. A regenerative repeater is considered. The effects of satellite nonlinearity and mobile channel on the performance of both systems have been considered. A frequency non-selective fading has been assumed. The combined effect of the traveling wave tube (TWT) power amplifier which exhibits AM/AM and AM/PM conversions and the multipath fading and shadowing of the mobile channel in addition to the additive white Gaussian noise (AWGN) are taken into consideration in the analysis. The effect of the TWT back-off from saturation which determines the degree of nonlinearity has also been taken into account. An expression for the error probabilities for both systems are derived and computed numerically.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114645881","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
Study of the coupling performance of multimode optical fiber coupler 多模光纤耦合器耦合性能研究
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760883
A. El-Fadl, G.E. Elabiad, S. Eladl, M. Rageh
{"title":"Study of the coupling performance of multimode optical fiber coupler","authors":"A. El-Fadl, G.E. Elabiad, S. Eladl, M. Rageh","doi":"10.1109/NRSC.1999.760883","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760883","url":null,"abstract":"The coupling characteristics of two-core multimode fiber coupler are studied. A theoretical model solution of the wave equation for a multimode optical fiber for computing its propagation is analyzed. In addition, the dependence of the coupling efficiency on the wavelength, the separation between the two cores and the refractive index is studied. The effect of the length of the coupling region along the two-multimode core fiber coupler and the refractive index on the coupling characteristics is also investigated. The obtained results are agree with the physical performance of the multimode optical fiber coupler.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116044147","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: 2
On the separation of air flow during phonation 关于发声过程中气流的分离
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760936
M. Hesham
{"title":"On the separation of air flow during phonation","authors":"M. Hesham","doi":"10.1109/NRSC.1999.760936","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760936","url":null,"abstract":"The separation of air flow inside the vocal tract has been noticed experimentally in many works. In this work, some sort of such separation can be computed numerically using a simplified linear form of Navier-Stokes equations inside the vocal tract. The simplified set of flow equations preserves both the linearity of simple models and viscous losses of the natural phonation process. These equations are solved within two contiguous domains based on the boundary-layer theorem for compressible, low density and low viscosity fluids. The solution within the bulk of the vocal tract is easily conducted using the reflection-type line analog model. The momentum equation is a second order linear partial differential equation since it contains the viscosity effect. This equation, is, then, solved within the boundary layer which is adjacent to the vocal tract walls with time varying boundary conditions. This solution gives the velocity distribution of fluid flow which exhibits a separation. This approach afford a simple and fast linear solution which elaborates such complex behavior of air flow inside the vocal tract.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132460562","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
A simple analytical, approach to optical rib waveguides 光肋波导的简单分析方法
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760882
A.M. Zaghlous, A.A. Abou-El-Fadl
{"title":"A simple analytical, approach to optical rib waveguides","authors":"A.M. Zaghlous, A.A. Abou-El-Fadl","doi":"10.1109/NRSC.1999.760882","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760882","url":null,"abstract":"An algorithm is developed for calculating the dispersion characteristics and field distribution of rib optical waveguides for both quasi-TM and TE modes. The algorithm is based on the effective index method, which have been applied as a simple approach to treat the rib waveguides. The effect of the waveguide dimensions and parameters on the propagation constants is also studied. The obtained results show good agreement with other published data.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132090736","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: 5
Switched capacitor PLL frequency synthesizer 开关电容锁相环频率合成器
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760888
M. A. El-Ela
{"title":"Switched capacitor PLL frequency synthesizer","authors":"M. A. El-Ela","doi":"10.1109/NRSC.1999.760888","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760888","url":null,"abstract":"A technique for high resolution frequency synthesizer is introduced and analyzed. This technique is based on a duty cycle controlled oscillator circuit used as a fractional frequency divider placed in the feedback path of a phase locked loop. A design example is given with experimental results.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125484736","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
Determination of Pu-239 for nuclear material safeguards verification purposes 用于核材料保障核查目的的钚-239的测定
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1999-02-23 DOI: 10.1109/NRSC.1999.760953
S. El-Mongy, W.A.M. El-Gamal
{"title":"Determination of Pu-239 for nuclear material safeguards verification purposes","authors":"S. El-Mongy, W.A.M. El-Gamal","doi":"10.1109/NRSC.1999.760953","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760953","url":null,"abstract":"This work aims at measurement of Pu-239 for nuclear materials safeguards verification purposes. The work was carried out at Los-Alamos National Lab, (USA). Due to the strategic nature of the element, few samples were available to be assayed. The gamma spectrometric non-destructive assay technique was used for determining amount of Pu in the samples. A correction factor for self-attenuation due to the Pu matrix was made. The results show that the declared (certified) and measured (verified) values of Pu-239 agree with an average precision of about 0.40%.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"467 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127000778","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
Extremely small high power MW broadcasting antennas 极小的高功率毫瓦广播天线
Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249) Pub Date : 1997-09-12 DOI: 10.1109/NRSC.1999.760881
F. M. Kabbary, M. Khattab, A. Fayoumi, A. Swidan, M. C. Hately
{"title":"Extremely small high power MW broadcasting antennas","authors":"F. M. Kabbary, M. Khattab, A. Fayoumi, A. Swidan, M. C. Hately","doi":"10.1109/NRSC.1999.760881","DOIUrl":"https://doi.org/10.1109/NRSC.1999.760881","url":null,"abstract":"The paper describes the reasoning behind a very small but efficient antenna now being used in several daily services for AM broadcasting on medium wave. The design methodology is outlined and there is a plot of the field strength measured for one of the early services in 1992. Not only is the antenna wide band, but it is more efficient than normal monopole antennas, and therefore allows a reduction in power costs when radiating comparable signal strength.","PeriodicalId":250544,"journal":{"name":"Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116015005","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: 3
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