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Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Les auteurs analysent le comportement aléatoire d'un faisceau recevant plusieurs flux de trafic non poissonnien. Les trafics offerts sont modélisés à l'aide de fonctions de Cox et on montre comment passer de cette représentation à une représentation classique par des moments du trafic. A l'aide des transformées de Laplace des distributions des temps d'interarrivées des différents flux de trafic, on obtient les valeurs exactes des moments des flux en débordement et écoulé, même dans le cas où on offre plus d'un flux de trafic au faisceau. The authors analyse the stochastic behaviour of a trunk group offered several streams of non-Poissonian traffic. Offered streams are modelled using Cox functions and we show how to pass from this representation to a classical representation in terms of the moments of the traffic process. Using the Laplace transforms of the inter arrival time distributions of the different traffic streams, we obtain exact values for the moments of the overflow and carried streams, even when more than one traffic stream is offered to the trunk group. [ABSTRACT FROM AUTHOR]

Dans certaines parties du réseau téléphonique français, le trafic présente d'importantes variations saisonnières. Le présent article concerne une procédure de prévision du trafic à court terme basée sur l'analyse de séries chronologiques et destinée à être utilisée pour intégrer ces variations saisonnières dans le processus de planification. Deux méthodes de prévision sont étudiées - le lissage exponentiel (méthode de Holt-Winters) et la méthode plus élaborée de Box-Jenkins - et appliquées aux données du sousréseau de la Côted'Azur. La qualité de la modélisation s'avère meilleure avec la méthode de Box-Jenkins qu'avec celle de Holt-Winters. Une approche pour automatiser en partie la méthode de Box-Jenkins, afin de rendre la mise en œuvre plus facile, est enfin présentée. There are substantial seasonal variations in traffic in some parts of the French telephone network. This paper deals with a shortterm traffic forecasting procedure based on time series analysis for use in integrating these seasonal variations in the planning process. Two forecasting methods are investigated - exponential smoothing (Holt-Winters method) and the more sophisticated Box-Jenkins method- and applied to data on the French Riviera subnetwork. The quality of modelling is shown to be better with the Box-Jenkins method than with the Holt-Winters one. An approach is presented for partly automating the Box-Jenkins method, making the forecasting procedure easier to implement. [ABSTRACT FROM AUTHOR]

Les émetteurs de radiodiffusion en ondes kilométriques et hectométriques induisent sur le réseau téléphonique local proche des tensions perturbatrices de niveaux élevés. L'emploi de l'électronique rend ce réseau de plus en plus sensible à ces perturbations. Cet article résume les travaux menés au Cnet sur ce sujet; il met en évidence la sensibilité du réseau local et des terminaux d'abonnés, et propose des solutions pour éliminer ces perturbations. High power low and medium frequency broadcasting radio transmitter antennas induce high level perturbing voltages on adjacent local networks. New electronic telephone systems are particularly sensitive to these perturbations. The purpose of this paper is to demonstrate the sensitivity of local networks and subscriber systems to parasitic voltages and to provide solutions for their elimination. [ABSTRACT FROM AUTHOR]

L'auteur se propose de déterminer les pertes individuelles subies par chaque courant de trafic dans un réseau hiérarchisé, exploité en appels perdus, avec une répartition arbitraire pour la durée des communications. La recherche de lois de distribution propres à chaque courant de trafic conduit à les modifier au point que le concept habituel de «source de trafic», commode pour isoler une partie du réseau, ne convient pas. Il y a donc lieu d'être prudent sur les méthodes d'approximation par ajustement des premiers moments des lois de distribution d'états. On montre que les trafics «pseudo - poissonniens» se combinent en sommes «pondérées» de trafics pseudopoissonniens, où les coefficients de pondération sont des valeurs frontières aux propriétés différentes et directement liées aux probabilités de blocage de bout en bout. The author considers the problem of determining the individual loss probabilities of each traffic stream in a hierarchical network operated as a loss system in the case of arbitrary call holding time distribution. He shows that, in order to separate out the distribution function of each traffic stream, it is necessary to modify not only the arrival processes but also the call holding time distribution functions. The usual concept of «traffic source», which is convenient for isolating a part of the network, no longer applies. Therefore care must be exercised when applying approximate occupancy distribution moment matching methods. «Pseudo - Poisson» traffics are shown to combine in «weighted» sums of pseudo-Poisson traffics. The weighting coefficients are boundary values having different properties and are directly related to end to end blocking probabilities. [ABSTRACT FROM AUTHOR]

Cet article décrit des algorithmes de codage différentiel utilisant des prédicteurs à filtres en treillis pour le codage de la parole et présente leurs performances en présence ou non d'erreurs de transmission. L'analyse statistique des résultats des tests subjectifs montre que l'utilisation de ces algorithmes pour le codage de la parole permet de diviser par deux le débit numérique que nécessite le codage mic classique. L'article montre que, pour les codeurs testés, les meilleures performances subjectives sont obtenues avec des prédicteurs en treillis. Le comportement de ces algorithmes dans les configurations de codages et de transcodages multiples à partir de codes mic, que l'on peut rencontrer dans le réseau téléphonique actuel est abordé en fin d'article. This paper describes several speech coding algorithms using adaptive differential pulse code modulation ( adpcm) and gives subjective and objective results without and with transmission errors. Subjective results show that these algorithms allow a reduction of the standard pcm bit rate by a factor 2. The best results are obtained by adaptive lattice predictors. The behaviour of the described algorithms in some configuration that will appear in the telephone network, i.e. multiple codings and transcodings from pcm, is also studied. [ABSTRACT FROM AUTHOR]

Ce deuxième congrès, consacré à la planification des réseaux de télécommunication, a réuni plusieurs centaines de spécialistes venus d'une trentaine de pays. Les thèmes abordés ont couvert l'ensemble des réseaux publics et privés, existants et futurs et les grands problèmes actuels : outils de planification, numérisation, sécurisation, intégration des réseaux et services. Après avoir précisé la participation du Cnet, on présente, regroupées par thèmes, les principales contributions. During this second Telecommunication Network Planning Symposium, several hundreds of delegates from thirty countries met together. The discussed topics covered public and private, existing and future networks and important present problems : planning tools, digitalization, securization, integration of networks and services. After a presentation of Cnet participation, the authors describe the main contributions, classified in different topics. [ABSTRACT FROM AUTHOR]

Dans cet article l'auteur présente une nouvelle technique de transmission : l'annulation d'écho. Après un exposé des principes de base et des difficultés de réalisation qui peuvent apparaître au premier abord, on montre que des simplifications importantes sont possibles dans le cas de transmissions de données au débit binaire de 2 400 bit/s. Une réalisation pratique d'un annuleur d'écho utilisé dans un modem 2 400 bit/s est ensuite décrite ainsi que les performances de ce dispositif. In this paper, a new transmission technique is presented :the echo cancellation. After a description of its basic principles and of the implementation difficulties which may appear at first, it is shown that important simplifications are possible in the case of data transmissions at 2 400 bit/s data bit rate. A practical realisation of an echo canceller used in a 2 400 bit/s modem is then described and the performances of this device are given. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)