Pub Date : 1989-04-11DOI: 10.1109/MELCON.1989.50043
S. Sait, A. F. Damati, M. Rahman
A novel systolic architecture for Viterbi decoding is presented. It consists of two blocks of processors. The first contains a column of processors which perform branch metric computation and decide on the survived branches. The second consists of a matrix of simpler processors which update survived paths and provide the decoded output. The systolic algorithm is modeled in AHPL to verify functional correctness. Implementation details are discussed. It is found that the proposed systolic design compares favorably with previous implementations of Viterbi decoders in terms of speed and modularity.<>
{"title":"A systolic algorithm for VLSI design of a 1/N rate Viterbi decoder","authors":"S. Sait, A. F. Damati, M. Rahman","doi":"10.1109/MELCON.1989.50043","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50043","url":null,"abstract":"A novel systolic architecture for Viterbi decoding is presented. It consists of two blocks of processors. The first contains a column of processors which perform branch metric computation and decide on the survived branches. The second consists of a matrix of simpler processors which update survived paths and provide the decoded output. The systolic algorithm is modeled in AHPL to verify functional correctness. Implementation details are discussed. It is found that the proposed systolic design compares favorably with previous implementations of Viterbi decoders in terms of speed and modularity.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"54 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":"123246944","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.1989.50085
J. Kanellopoulos, S. Ventouras
A model for the prediction of triple site diversity performance based on the three-dimensional gamma distribution is proposed. The proposed method is based on the convective raincell model for the spatial structure of the rainfall medium. The model is oriented toward application to earth-space paths located in Japan and other locations with similar climatic conditions. Numerical results are compared with a limited set of available experimental data, and some conclusions are given.<>
{"title":"A predictive analysis of the advantage of triple site diversity satellite systems (gamma distribution case)","authors":"J. Kanellopoulos, S. Ventouras","doi":"10.1109/MELCON.1989.50085","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50085","url":null,"abstract":"A model for the prediction of triple site diversity performance based on the three-dimensional gamma distribution is proposed. The proposed method is based on the convective raincell model for the spatial structure of the rainfall medium. The model is oriented toward application to earth-space paths located in Japan and other locations with similar climatic conditions. Numerical results are compared with a limited set of available experimental data, and some conclusions are given.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"128 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":"115556788","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.1989.50137
J. Kanellopoulos, N. Stathopoulos
By applying Fourier transformations to Maxwell's equations, the authors derive transmission-line equations representing the transverse electric (TE) and transverse magnetic (TM) modes of dielectric planar layers. The propagation constant of any mode can be found from the resonance conditions of the T-circuit representation of the transmission line. The method developed for the linear case is extended to include the nonlinear waves guided by such structures. The following realistic material systems are treated: a cladding medium with either a self-focusing or a self-defocusing nonlinearity and bounding media with all combinations of self-focusing and self-defocusing nonlinearities. Dielectric films with arbitrary refractive index profiles bounded by nonlinear media are examined. Useful results concerning the field distribution and the guided power versus propagation constant are derived.<>
{"title":"Equivalent circuits in Fourier space for the study of nonlinear waves guided by thin films","authors":"J. Kanellopoulos, N. Stathopoulos","doi":"10.1109/MELCON.1989.50137","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50137","url":null,"abstract":"By applying Fourier transformations to Maxwell's equations, the authors derive transmission-line equations representing the transverse electric (TE) and transverse magnetic (TM) modes of dielectric planar layers. The propagation constant of any mode can be found from the resonance conditions of the T-circuit representation of the transmission line. The method developed for the linear case is extended to include the nonlinear waves guided by such structures. The following realistic material systems are treated: a cladding medium with either a self-focusing or a self-defocusing nonlinearity and bounding media with all combinations of self-focusing and self-defocusing nonlinearities. Dielectric films with arbitrary refractive index profiles bounded by nonlinear media are examined. Useful results concerning the field distribution and the guided power versus propagation constant are derived.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"45 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":"115657362","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.1989.50038
P. Cordell, R. Clarke
The quadtree-based interpolative recursive binary nesting technique is described, and methods of converting the algorithm from one used to code still pictures into one suitable for moving sequences at 64 kb/s are outlined. The implications of various forms of block testing, quantization, and motion compensation are discussed and compared, and areas requiring further work are noted. It is shown that the disturbing effects that are produced by using the original algorithm for moving sequence coding can be overcome and that motion compensation can be effectively applied to the coding procedure. A flow diagram of the complete system is included.<>
{"title":"Moving image sequence coding using recursive binary nesting","authors":"P. Cordell, R. Clarke","doi":"10.1109/MELCON.1989.50038","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50038","url":null,"abstract":"The quadtree-based interpolative recursive binary nesting technique is described, and methods of converting the algorithm from one used to code still pictures into one suitable for moving sequences at 64 kb/s are outlined. The implications of various forms of block testing, quantization, and motion compensation are discussed and compared, and areas requiring further work are noted. It is shown that the disturbing effects that are produced by using the original algorithm for moving sequence coding can be overcome and that motion compensation can be effectively applied to the coding procedure. A flow diagram of the complete system is included.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"34 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":"115797683","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.1989.50059
D. Tesla
A simple and cost-effective real-time channel evaluation method suitable for quick channel ranking in adaptive HF systems is suggested. Intended to provide bit error rate monitoring, the proposed method is based on a modification of Gooding's (1968) pseudo error monitoring (PEM) scheme. It is shown that the method can be easily implemented in microprocessor technology at moderate cost. A model of the PEM monitor was realized and thoroughly tested under different conditions. The results obtained are satisfactory; hence, it can be concluded that the proposed method is suitable for adaptive HF systems applications.<>
{"title":"A method of quick channel ranking in adaptive HF systems","authors":"D. Tesla","doi":"10.1109/MELCON.1989.50059","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50059","url":null,"abstract":"A simple and cost-effective real-time channel evaluation method suitable for quick channel ranking in adaptive HF systems is suggested. Intended to provide bit error rate monitoring, the proposed method is based on a modification of Gooding's (1968) pseudo error monitoring (PEM) scheme. It is shown that the method can be easily implemented in microprocessor technology at moderate cost. A model of the PEM monitor was realized and thoroughly tested under different conditions. The results obtained are satisfactory; hence, it can be concluded that the proposed method is suitable for adaptive HF systems applications.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"276 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":"131614247","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.1989.49995
F. Smole, J. Furlan, S. Amon, D. Sencar
Results of a computer analysis of a p-i-n structure a-Si:H solar cell for different impurity gradients of p-i transitions and for various added acceptor and donor impurities in the i-layer are presented. It was found that the impurity gradient of a p-i transition in the p-i-n structure of an a-Si:H solar cell, when the illumination is incident on the p/sup +/-layer, has little influence on cell optoelectrical properties. This is true as long as the p-layer does not penetrate too deeply into the i-layer. Acceptor impurities, added into the i-layer, lower cell efficiency strongly, while the addition of donor impurities reduces cell properties only slightly.<>
{"title":"Effects of internal structure on electrical properties of a-Si:H solar cell","authors":"F. Smole, J. Furlan, S. Amon, D. Sencar","doi":"10.1109/MELCON.1989.49995","DOIUrl":"https://doi.org/10.1109/MELCON.1989.49995","url":null,"abstract":"Results of a computer analysis of a p-i-n structure a-Si:H solar cell for different impurity gradients of p-i transitions and for various added acceptor and donor impurities in the i-layer are presented. It was found that the impurity gradient of a p-i transition in the p-i-n structure of an a-Si:H solar cell, when the illumination is incident on the p/sup +/-layer, has little influence on cell optoelectrical properties. This is true as long as the p-layer does not penetrate too deeply into the i-layer. Acceptor impurities, added into the i-layer, lower cell efficiency strongly, while the addition of donor impurities reduces cell properties only slightly.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"9 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":"127031986","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.1989.50025
S. Ragazzini, L. Prina Ricotti, G. Martinelli, C. Borromeo
The performance obtained using a self-organizing neural network for the vector quantization of the reflection coefficients of a nonstationary lattice is considered. The training of the neural network is effected on a small number of speech patterns of one speaker and subsequently tested on different patterns of the same speaker. The use of a self-organizing neural network for quantizing the parameters representing a nonstationary lattice has evidenced an important property of this network when used as a quantizer, i.e., its inherent ability to generalize. When used in connection with speech, the network has been able to behave well in situations different from those considered in the training.<>
{"title":"A neural network quantizer for long term vocal tract characterization","authors":"S. Ragazzini, L. Prina Ricotti, G. Martinelli, C. Borromeo","doi":"10.1109/MELCON.1989.50025","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50025","url":null,"abstract":"The performance obtained using a self-organizing neural network for the vector quantization of the reflection coefficients of a nonstationary lattice is considered. The training of the neural network is effected on a small number of speech patterns of one speaker and subsequently tested on different patterns of the same speaker. The use of a self-organizing neural network for quantizing the parameters representing a nonstationary lattice has evidenced an important property of this network when used as a quantizer, i.e., its inherent ability to generalize. When used in connection with speech, the network has been able to behave well in situations different from those considered in the training.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"63 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":"124376649","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.1989.50060
G. Bartolucci, G. Leuzzi, C. Paoloni, M. Ruggieri
Some results of a study on active antennas for communications satellites are presented. A comparison between the performances of the antenna system in the two cases of a beam forming network (BFN) at low (IF) or high (RF) frequency is carried out, and the results are presented. The comparison is performed from the point of view of total weight, size, bandwidth, and reliability for a near-field multibeam antenna covering Western Europe. In the case of a low-frequency BFN the system is formed by a diode matrix followed by 37 chains of two cascaded mixers for the two-step up-conversion. The prevailing mass contribution comes from the mixers, even if they are refunded, while the use of the active matrix has the greater impact on reliability and bandwidth limitation. In the case of a high-frequency BFN the single or double (cascaded) bank of 14 mixers is followed by a hybrid BFN. The mixers, even if fully redundant and with a two-step up-conversion, are fewer in number, and therefore lighter, than in the previous case, while the reliability is ensured to a good level.<>
{"title":"On-board electronics for an active near field multibeam","authors":"G. Bartolucci, G. Leuzzi, C. Paoloni, M. Ruggieri","doi":"10.1109/MELCON.1989.50060","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50060","url":null,"abstract":"Some results of a study on active antennas for communications satellites are presented. A comparison between the performances of the antenna system in the two cases of a beam forming network (BFN) at low (IF) or high (RF) frequency is carried out, and the results are presented. The comparison is performed from the point of view of total weight, size, bandwidth, and reliability for a near-field multibeam antenna covering Western Europe. In the case of a low-frequency BFN the system is formed by a diode matrix followed by 37 chains of two cascaded mixers for the two-step up-conversion. The prevailing mass contribution comes from the mixers, even if they are refunded, while the use of the active matrix has the greater impact on reliability and bandwidth limitation. In the case of a high-frequency BFN the single or double (cascaded) bank of 14 mixers is followed by a hybrid BFN. The mixers, even if fully redundant and with a two-step up-conversion, are fewer in number, and therefore lighter, than in the previous case, while the reliability is ensured to a good level.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"10 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":"114300467","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.1989.50010
J. Hylander, S. von Zweygbergk
A method for reducing the influence of current harmonics in variable-speed drives on electrodynamic torque has been analyzed with experiments and calculations. An 11 kW 380 V induction motor was rewound with two three-phase systems displaced 30 electrical degrees. Measurements were made with quasi-square-wave supply generated by two voltage source inverters. The induction machine was coupled via a torque transducer to a DC machine. The voltage, two phase currents, and the torque were measured with a transient recorder connected to a computer. In the computer the data were processed with a fast Fourier transform program in order to determine the harmonics. Calculations were also made on a transient computer model of the drive. It is shown that, by designing an induction machine with an extra set of three-phase winding, displaced 30 electrical degrees from the ordinary winding, the influence of the 5, 7, 17, 19, . . . current harmonics on the torque is eliminated. Only the 11, 13, 23, 25, . . . harmonics still produce pulsating torques. The drawback is the extra inverter and winding.<>
{"title":"Induction machines with two three-phase windings in convertor applications","authors":"J. Hylander, S. von Zweygbergk","doi":"10.1109/MELCON.1989.50010","DOIUrl":"https://doi.org/10.1109/MELCON.1989.50010","url":null,"abstract":"A method for reducing the influence of current harmonics in variable-speed drives on electrodynamic torque has been analyzed with experiments and calculations. An 11 kW 380 V induction motor was rewound with two three-phase systems displaced 30 electrical degrees. Measurements were made with quasi-square-wave supply generated by two voltage source inverters. The induction machine was coupled via a torque transducer to a DC machine. The voltage, two phase currents, and the torque were measured with a transient recorder connected to a computer. In the computer the data were processed with a fast Fourier transform program in order to determine the harmonics. Calculations were also made on a transient computer model of the drive. It is shown that, by designing an induction machine with an extra set of three-phase winding, displaced 30 electrical degrees from the ordinary winding, the influence of the 5, 7, 17, 19, . . . current harmonics on the torque is eliminated. Only the 11, 13, 23, 25, . . . harmonics still produce pulsating torques. The drawback is the extra inverter and winding.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"153 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":"114642525","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.1989.49983
E. Fornasini, G. Marchesini
Dynamic redundancy relations of two-dimensional systems allow for an implementation of parity checks by means of two-dimensional dynamic models. The authors present a complete characterization of the admissible parity checks in the formal power series domain and provide a dynamic implementation which does not increase the intrinsic delays of the failure detection process. The parity checks are represented as elements of a free module over the ring of polynomials in two variables, whose structure is completely specified by a finite set of generators computed from the matrix fraction description of the system. Also presented is an explicit realization procedure of the polynomial matrix in two variables that constitutes the transfer matrix of the corresponding residual generator.<>
{"title":"Residual generators for detecting failure in 2D systems","authors":"E. Fornasini, G. Marchesini","doi":"10.1109/MELCON.1989.49983","DOIUrl":"https://doi.org/10.1109/MELCON.1989.49983","url":null,"abstract":"Dynamic redundancy relations of two-dimensional systems allow for an implementation of parity checks by means of two-dimensional dynamic models. The authors present a complete characterization of the admissible parity checks in the formal power series domain and provide a dynamic implementation which does not increase the intrinsic delays of the failure detection process. The parity checks are represented as elements of a free module over the ring of polynomials in two variables, whose structure is completely specified by a finite set of generators computed from the matrix fraction description of the system. Also presented is an explicit realization procedure of the polynomial matrix in two variables that constitutes the transfer matrix of the corresponding residual generator.<<ETX>>","PeriodicalId":380214,"journal":{"name":"Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering',","volume":"60 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":"114586250","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：