Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50112
J. Budin
The total (material and waveguide) dispersion of step-index single-mode fibers with perturbed refractive index profiles is studied. The perturbation solution is shown to lead to a simple evaluation of the fiber zero dispersion wavelength. Various models of perturbed fiber profiles are examined, and their influences on the zero-dispersion shift are compared. It is shown that the resulting zero-dispersion shift, although small, should be taken into consideration.<>
{"title":"Determination of the zero-dispersion shift in single-mode fibers with perturbed index-profile","authors":"J. Budin","doi":"10.1109/MELCON.1989.50112","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50112","url":null,"abstract":"The total (material and waveguide) dispersion of step-index single-mode fibers with perturbed refractive index profiles is studied. The perturbation solution is shown to lead to a simple evaluation of the fiber zero dispersion wavelength. Various models of perturbed fiber profiles are examined, and their influences on the zero-dispersion shift are compared. It is shown that the resulting zero-dispersion shift, although small, should be taken into consideration.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125725096","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50131
M.A. Ossorio, A. Villalobos, E. Fustero, L. Nicolas, F. Fuertes
The authors present a comparative study of alternative methods for interconnection of FDDI (fiber distributed data interface) networks with ISDN environments. The methods studied include the connection between FDDI and a PBX with ISDN services via a gateway, and direct connection between FDDI and a CCITT standardized ISDN interface with the call setup and switching functions performed either outside the FDDI network via a PBX or inside the FDDI network. A design philosophy is given based on the concepts and principles of the OSI reference model and focused on the realization of an S-interface connection to the FDDI.<>
{"title":"A comparative study of alternative methods for FDDI and ISDN environments interconnection","authors":"M.A. Ossorio, A. Villalobos, E. Fustero, L. Nicolas, F. Fuertes","doi":"10.1109/MELCON.1989.50131","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50131","url":null,"abstract":"The authors present a comparative study of alternative methods for interconnection of FDDI (fiber distributed data interface) networks with ISDN environments. The methods studied include the connection between FDDI and a PBX with ISDN services via a gateway, and direct connection between FDDI and a CCITT standardized ISDN interface with the call setup and switching functions performed either outside the FDDI network via a PBX or inside the FDDI network. A design philosophy is given based on the concepts and principles of the OSI reference model and focused on the realization of an S-interface connection to the FDDI.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129424194","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50115
P.D. Sparaggis, M. Anagnostou, G. Stassinopoulos, E. Protonotarios
The modeling of asynchronous transfer mode proposals in IBCNs is addressed. Asynchronous multiplexing has been proposed as an effective and flexible technique for handling the different traffic types in IBCNs (integrated broadband communication networks) in a uniform way. The authors present the queuing superposition of L independent equivalent deterministic arrival streams, with the service times also being deterministic. They derive an explicit formula for the queue length distribution in the steady state, explore the properties of the queuing process, and associate the proposed model with important performance parameters such as the buffer occupancy and the channel utilization.<>
{"title":"Analysis of asynchronous multiplexers for periodic traffic in integrated broadband networks","authors":"P.D. Sparaggis, M. Anagnostou, G. Stassinopoulos, E. Protonotarios","doi":"10.1109/MELCON.1989.50115","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50115","url":null,"abstract":"The modeling of asynchronous transfer mode proposals in IBCNs is addressed. Asynchronous multiplexing has been proposed as an effective and flexible technique for handling the different traffic types in IBCNs (integrated broadband communication networks) in a uniform way. The authors present the queuing superposition of L independent equivalent deterministic arrival streams, with the service times also being deterministic. They derive an explicit formula for the queue length distribution in the steady state, explore the properties of the queuing process, and associate the proposed model with important performance parameters such as the buffer occupancy and the channel utilization.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123739014","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50126
E. Carrieri, C. A. Rocchini, A. Fioretti, A.J. Haylett
An OSI (open systems interconnection) compatible architecture for a multichannel integrated network is defined. The OSI layers considered are the lowest three because the network structure affects only these layers. The authors analyze the services to be provided by each layer and derive the related primitives. Some of these primitives are the same as in a conventional network, while new primitives have been introduced due to the multichannel nature of the network. After a brief description of each layer, the primitives are presented together with their parameters and the data structures used. For each layer's and layer manager's primitives and services, a detailed logical description is given.<>
{"title":"An OSI compatible architecture for integrated multichannel metropolitan and regional networks","authors":"E. Carrieri, C. A. Rocchini, A. Fioretti, A.J. Haylett","doi":"10.1109/MELCON.1989.50126","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50126","url":null,"abstract":"An OSI (open systems interconnection) compatible architecture for a multichannel integrated network is defined. The OSI layers considered are the lowest three because the network structure affects only these layers. The authors analyze the services to be provided by each layer and derive the related primitives. Some of these primitives are the same as in a conventional network, while new primitives have been introduced due to the multichannel nature of the network. After a brief description of each layer, the primitives are presented together with their parameters and the data structures used. For each layer's and layer manager's primitives and services, a detailed logical description is given.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130484009","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.49994
J. Pereira
The effects of doping on the electrical and optical properties of RF-sputtered a-Si/sub x/Ge/sub 1-x/:H (x=0.70) are investigated. The films were deposited at a constant substrate temperature of 200 degrees C, and n and p-doped samples were obtained by introducing controlled amounts of phosphine and diborane, respectively, in the sputtering atmosphere. The conductivity increased by about two orders of magnitude for the n-type samples and by one order of magnitude for the p-type samples. Thermoelectric power measurements confirmed that doping was achieved. The optical gap did not seem to vary upon doping. The presence of germanium and oxygen is responsible for an increase of the localized states in the gap and of the width of the conduction band tail states. Therefore, these films show less sensitivity to doping than those of a-Si:H deposited under similar conditions. A model for the density of states in the gap, which includes the effects of impurities (oxygen), , is presented in order to explain the observed results.<>
{"title":"Electrical and optical properties of doped a-SiGe:H deposited by RF-sputtering","authors":"J. Pereira","doi":"10.1109/MELCON.1989.49994","DOIUrl":"https://doi.org/10.1109/MELCON.1989.49994","url":null,"abstract":"The effects of doping on the electrical and optical properties of RF-sputtered a-Si/sub x/Ge/sub 1-x/:H (x=0.70) are investigated. The films were deposited at a constant substrate temperature of 200 degrees C, and n and p-doped samples were obtained by introducing controlled amounts of phosphine and diborane, respectively, in the sputtering atmosphere. The conductivity increased by about two orders of magnitude for the n-type samples and by one order of magnitude for the p-type samples. Thermoelectric power measurements confirmed that doping was achieved. The optical gap did not seem to vary upon doping. The presence of germanium and oxygen is responsible for an increase of the localized states in the gap and of the width of the conduction band tail states. Therefore, these films show less sensitivity to doping than those of a-Si:H deposited under similar conditions. A model for the density of states in the gap, which includes the effects of impurities (oxygen), , is presented in order to explain the observed results.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126649127","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50133
S. Casale, V. Catania, A. Puliafito, L. Vita
The authors present a hierarchical three-level MAN (metropolitan area network) which is capable of interconnecting a large number of LANs (local area networks). They also propose a routing strategy based on a spanning-tree-type algorithm which allows optimization of reconfiguration times thanks to the possibility of selective network reconfiguration, and a limited extension of the filtering database, even in networks of metropolitan dimensions. A possible implementation of the MAN is suggested.<>
{"title":"Spanning tree algorithm for routing in hierarchical MANs","authors":"S. Casale, V. Catania, A. Puliafito, L. Vita","doi":"10.1109/MELCON.1989.50133","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50133","url":null,"abstract":"The authors present a hierarchical three-level MAN (metropolitan area network) which is capable of interconnecting a large number of LANs (local area networks). They also propose a routing strategy based on a spanning-tree-type algorithm which allows optimization of reconfiguration times thanks to the possibility of selective network reconfiguration, and a limited extension of the filtering database, even in networks of metropolitan dimensions. A possible implementation of the MAN is suggested.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121624385","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50154
I. Rozman, J. Gyorkos, P. Kokol, T. Welzer
An attempt is made to decide which formal software development methodology should be used to introduce software engineering to the electrical engineer. Two methodologies are compared: system analysis-system-design (SASD) and Jackson System Development (JSD). Nine postgraduate students of electrical engineering took part in this experiment. Each of them had to solve a specific problem according to both methodologies. A questionnaire was filled out by each student. The results obtained favor the SASD methodology because it is more understandable by an electrical engineer.<>
{"title":"Software engineering: how to approach it the electrical engineer","authors":"I. Rozman, J. Gyorkos, P. Kokol, T. Welzer","doi":"10.1109/MELCON.1989.50154","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50154","url":null,"abstract":"An attempt is made to decide which formal software development methodology should be used to introduce software engineering to the electrical engineer. Two methodologies are compared: system analysis-system-design (SASD) and Jackson System Development (JSD). Nine postgraduate students of electrical engineering took part in this experiment. Each of them had to solve a specific problem according to both methodologies. A questionnaire was filled out by each student. The results obtained favor the SASD methodology because it is more understandable by an electrical engineer.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"4 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114111463","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50065
M. Abu-Regheff, N. K. AL-Shamma, A.N. Sleiman, W.A. Al-gailani
A system capable of canceling continuous wave (CW) interference in direct-sequence spread-spectrum signals has been constructed. The system is based on a stepped sweeping phase-locked loop (PLL). The system can function equally well when the interference drifts or sweeps at a rate less than the sweep rate of the PLL used. Practical results indicate that the system gives 23 dB improvement in the signal-to-interferer power ratio at the input of the spread-spectrum processor when the input signal-to-interferer power ratio is -12 dB.<>
{"title":"Cancellation of a sweeping CW interferer in direct sequence spread spectrum signals","authors":"M. Abu-Regheff, N. K. AL-Shamma, A.N. Sleiman, W.A. Al-gailani","doi":"10.1109/MELCON.1989.50065","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50065","url":null,"abstract":"A system capable of canceling continuous wave (CW) interference in direct-sequence spread-spectrum signals has been constructed. The system is based on a stepped sweeping phase-locked loop (PLL). The system can function equally well when the interference drifts or sweeps at a rate less than the sweep rate of the PLL used. Practical results indicate that the system gives 23 dB improvement in the signal-to-interferer power ratio at the input of the spread-spectrum processor when the input signal-to-interferer power ratio is -12 dB.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"271 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120988210","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50099
M. Santamaria, M. Lagunas, M. Cabrera
The authors describe the potential of neural net filters in communication systems. They consider applications of neural networks in those fields associated with communications where time-varying linear systems need to be used; the structure of the neural net considered is the multiple-layer feed-forward network. It is shown that an FIR (finite impulse response) filter with finite representation of its output could be viewed as a two-layer neural net. Experiments on the equalization of nonlinear communication channels with memory are reported, demonstrating the potential of neural networks in integrated tools for signal processing and decoding.<>
{"title":"Neural nets filters: integrated coding and signaling in communication systems","authors":"M. Santamaria, M. Lagunas, M. Cabrera","doi":"10.1109/MELCON.1989.50099","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50099","url":null,"abstract":"The authors describe the potential of neural net filters in communication systems. They consider applications of neural networks in those fields associated with communications where time-varying linear systems need to be used; the structure of the neural net considered is the multiple-layer feed-forward network. It is shown that an FIR (finite impulse response) filter with finite representation of its output could be viewed as a two-layer neural net. Experiments on the equalization of nonlinear communication channels with memory are reported, demonstrating the potential of neural networks in integrated tools for signal processing and decoding.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128113779","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}
Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50106
G. Junyent, S. Ruiz-Moreno, S. Ruiz-Boqué, J. Vall-llosera, M. Garcia-Sempere
The authors analyze the signal-to-noise ratio (SNR) at the photodetector output for a single-mode fiber optic digital transmission system including online optical amplifiers and an optical preamplifier. The effect of timing error on the performance of a direct detection PIN receiver is also studied. This allows an accurate design of the optical link in terms of the bit error rate desired (10/sup -9/ is required for optical communications). It is suggested that for a system with no timing error the signal-to-noise ratio at the photodetector output must be 21.6 dB. With timing uncertainty a higher SNR is necessary and, for a given value of n/sub s/, this allows the design of the link in terms of the gain or the optical amplifiers and their number in a more realistic way.<>
{"title":"Performance of the optical amplifier in fiber digital transmission systems with timing uncertainty","authors":"G. Junyent, S. Ruiz-Moreno, S. Ruiz-Boqué, J. Vall-llosera, M. Garcia-Sempere","doi":"10.1109/MELCON.1989.50106","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50106","url":null,"abstract":"The authors analyze the signal-to-noise ratio (SNR) at the photodetector output for a single-mode fiber optic digital transmission system including online optical amplifiers and an optical preamplifier. The effect of timing error on the performance of a direct detection PIN receiver is also studied. This allows an accurate design of the optical link in terms of the bit error rate desired (10/sup -9/ is required for optical communications). It is suggested that for a system with no timing error the signal-to-noise ratio at the photodetector output must be 21.6 dB. With timing uncertainty a higher SNR is necessary and, for a given value of n/sub s/, this allows the design of the link in terms of the gain or the optical amplifiers and their number in a more realistic way.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133767792","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}
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