Showing papers by "Deutsche Telekom published in 1994"

Transmissions of programme related signals for video selection

Abstract: A radio transmitter (1) transmits coded video signals to a receiver (2) and can be recorded (4) or displayed (3) after being decoded (5). The selection of the transmissions required can be made with the aid of a mobile telephone unit (7). The signals are transmitted over the mobile telephone network (8) and a data line (9) coupled to a management unit. This allows the appropriate decoding data to be selected.

Continuously distributed phase shifts in chirped DFB lasers using bent waveguides

Abstract: The authors have implemented chirped distributed feedback (DFB) grating lasers with phase shifts ( lambda /8, 2 lambda /8 and 3 lambda /8) distributed continuously over various axial distances, using their recently proposed method for producing bent optical waveguides. The singlemode stability of the lasers with distributed phase shifts was found to be considerably higher than for lasers with abrupt phase shifts. >

Study of wavelength shift in InGaAs/InAlGaAs QW DFB lasers based on laser parameters from a comparison of experiment and theory

Abstract: Experimental data of InGaAs/InAlGaAs quantum well distributed feedback (DFB) lasers such as spectra, under continuous and pulsed biasing, relative intensity noise and linewidth, are compared with the results of model calculations based on a transfer matrix method. Using experimental data of different lasers, a set of physical DFB laser parameters was determined. We succeeded in describing all the experimental data of different lasers by the same set. The determined parameter set was further applied to study the influence of facet properties on the wavelength shift of DFB lasers. We found a very strong dependence of the wavelength tunability on the end facet phases. The wavelength shift varies by a factor up to three between different end facet phases and coatings. This is crucial for the yield of, for example, tunable multisection DFB lasers with an envisaged large tuning range. >

Process for operating a mobile radiotelephone system utilizing subscriber indentification modules

Abstract: In a process for operating a mobile radiotelephone system in which mobile stations are actuated with the aid of an identification number transmitted from the mobile station concerned to an active system in that, after the identification number has been checked in the active system in a data set which contains at least the identification number and a call number allocated thereto, a status field is set to "active", and in which, on the receipt of a request for connection with a call number the active system checks whether that call number is active, in which, if there is a match, a connection is made using the call number, the data set contains a reference to a further data set which contains a further identification number, a further call number, a further status field and a reference to the data set. When a request for connection to the call number is received, if the latter is not active, a connection is made using the further data set if it is active.

Protecting data passing between data processing device and terminal device connected via telecommunications network

Abstract: The method involves using a code stored in a security module in each device for mutual authentication before commencing the transfer of data. Each code represents keys within an algorithm which processes random data fed to the terminal or data processor; the results of the processing are fed back to the data processor or terminal.The data are integrally protected when the code arrives, is stored in the terminal and transmitted using a message authentication code or MAC with the aid of algorithms and keys in each security module. Secure counters in the security modules perform additional monitoring of the data protected by the MAC.

Process for operating a mobile radiotelephone system

Abstract: In a process for operating a mobile radiotelephone system in which mobile stations are actuated with the aid of an identification number transmitted from the mobile station concerned to an active system in that, after the identification number has been checked in the active system in a data set which contains at least the identification number and a call number allocated thereto, a status field is set to 'active', and in which, on the receipt of a request for connection with a call number the active system checks whether that call number is active, in which, if there is a match, a connection is made using the call number, the data set contains a reference to a further data set which contains a further identification number, a further call number, a further status field and a reference to the data set. When a request for connection to the call number is received, if the latter is not active, a connection is made using the further data set if it is active.

Mobile radio communications network quality monitoring system

Abstract: The system uses mobile measurement segments (QvM,QvH), with at least one network signal transmitter, a computer with external data storage units and a position measurement system, and stationary measurement segments (QvS) with at least one network signal transmitter/receiver, a measurement data interface and an audio port on the interface for the conversion electrical to audio signals, an evaluation unit with at least one speech recognition and evaluation stage and a time and data measurement system.A stationary evaluation segment has a computer with units for reading and storing data and data display units. Automatic communications links are established between the mobile and stationary measurement segments depending on test programmes. All the measurement data are stored in the stationary evaluation segment which prepares the stored data for graphical and/or alphanumeric display.

Locating process for levying road toll charges

Abstract: The region where the mobile station is located within the respective cell is determined from a mobile station of a cellular mobile radio network by transit time difference measuring. The mobile station location within the region is determined by reception of a transmitter determining the location.Pref. the transit time difference measuring is carried out by measuring time difference during reception of the transmitter of the respective cell and several other transmitters of the mobile radio network.

The role of vertical transport and capture of electrons and holes for the transient optical response in quantum-well heterostructures

Abstract: The transient optical response of quantum wells (QWs) after optical and electrical carrier injection into the barrier layers is studied experimentally and theoretically. We have varied the transport geometry in GaAs/AlGaAs and InGaAs/InAlGaAs heterostructures and emphasize the basic principles for a theoretical treatment of electron and hole capture into QWs for a proper description of vertical carrier transport in the barriers of QW heterostructures. Comparing our experimental data with the results of theoretical model calculations, we determine the capture, reflection and transmission probabilities, the ambipolar diffusivities and the ambipolar mobilities in the barriers of GaAs/AlGaAs, as a model system. The temporal evolution of the electron and the hole capture current densities at the QWs are studied in detail for a wide variation of the injected carrier densities. Amplitude modulation experiments are performed for InGaAs/InAlGaAs QW laser devices providing increasing 3 dB frequencies for decreasing confinement layer thickness, indicating the influence of carrier transport in the barriers.

Specifying Business Processes over Objects

Abstract: The focus of this paper is on the modeling of application and business processes in Cooperative Information Systems. Such processes use several resources and services to achieve a common, global system goal. We integrate the proposed concepts into the framework of a formal object-oriented specification language (Troll). The goals of our approach are to provide additional modeling support for business and application processes, to explain these processes in the underlying framework and to couple tightly the modeling of global processes and the modeling of structural aspects of the system.

Bidirectional surveying method esp. for radio channel

Abstract: The method transmits a signal through a channel in a communications station and determines a measurement value. This value indicates the reception quality, as a function of time and location. The method simultaneously transmits signals produced by the mobile station, in a second channel. This signal is received in the fixed station by a measurement receiver. Measurement values which describe the quality of the second channel are recorded as a function of time and location. One of the time signals to be supplied to the measurement transmitter is modulated with the signal produced by the measurement transmitter. The time signal supplied to one of the measurement transmitters, which together with the time signals transmitted with the signals produced by one of the measurement transmitters, are recorded with the respective measurement value.

Universal application method for card end equipment

Abstract: The card end equipment is connected to a security module. The security module includes an assembly for testing the authenticity and the authorisation of value cards and an assembly for storage and documentation of the cancelled amounts on the value card. The data carrier which contains the debited amounts can only be removed in a protected procedure by an authorised person. Settlement with the manufacturer or distributor of the card is carried out on the basis of the data carrier.

An Evolutionary Approach For TMN Management Of Pan-European IN-Based Services

Abstract: This paper introduces the work being performed in EURESCOM (a research institute jointly owned by the majority of PNOs in Europe) on the management of pan-European IN-based services using a TMN approach. This work is currently being realised by the EURESCOM Project P226 with the support of the following participating companies: Telecom Portugal, BT, DBP Telekom, France Telecom, STET Italy, TLP Portugal, PTT Netherlands, Telefonica de Espana, Telecom Finland, Telecom Ireland and Swedish Telecom. The focus of this research project is to elaborate an evolutionary path for the management of IN-based services in Europe. The evolution approach is based on the definition of a long term scenario and on the development of both medium term and long term solutions for the provision of a set of generic management services and respective information models. This paper presents an overview of the project and some initial project results for a long term scenario as well as some intermediate results for a medium-term solution for the management of pan-European IN (PEIN) services. The initial results accomplished in the first phase of the work related to the definition of a long term scenario for IN management include: feedback from a questionaire to PNOs; definition of the IN management roles in a long term IN environment; identification of organizational models suitable for joint/co-operative IN management arrangements between PNOs in Europe; and collection of an initial set of IN management requirements. Intermediate results of the second phase (status of March 1994) related to the definition of an inter-PNO IN service management framework comprise: overview of the expected medium term IN environment; and definition of a generic medium term TMN management framework, comprising a set of suitable inter-PNO IN service management services and related management information as well as possible organisational models for the joint/cooperative provision of the identified IN management services between co-operating PNOs.

Verfahren und Vorrichtung zur mehrkanaligen Tonwiedergabe

Abstract: 2.1. Bei der mehrkanaligen Tonwiedergabe unter den Bedingungen der Heimwiedergabe und, besonders nach Ubertragung, auch fur grosere Raume, soll eine Vergroserung des Anteils der Gesamtraumgrose fur die akustisch/visuelle Nutzbarkeit erreicht werden, der fur die platzunabhangige Wiedergabe der Raum-(Surround-) Informationen bei Beibehaltung der vorgegebenen Richtungsinformation der einzelnen Tonsignalquellen nutzbar ist. 2.2. Bei dem Verfahren wird jedes Signal aufgeteilt und ein Teil mit einer vergroserten Laufzeit, einem veranderten Pegel, geanderter Phasenlage, nach einer Summenbildung jeweils einem der unveranderten Signalanteile zugefuhrt, wobei die Summensignale in Richtungszuordnung entsprechend den jeweiligen unveranderten Signalanteilen den zwei Surround-Wiedergabekanalen und zu weiteren im Raum verteilt angeordneten Wiedergabelautsprechern verteilt und zugefuhrt werden. Hierzu wird eine Vorrichtung, bestehend aus Matrix- und Bearbeitungsbausteinen zur elektroakustischen Anpassung und Optimierung vorgegebener Horzonen vorgeschlagen, bei der die Parameter der Wiedergabeanordnung gepruft und uber steuerbare Matrizierungs- und Bearbeitungsbausteine in den vorhandenen Wiedergabekanalen korrigiert werden. 2.3. Die Erfindung eignet sich fur die Wiedergabe ubertragener bzw. gespeicherter richtungsorientierter Tonsignale.

Integrated optical single side band modulator for microwave frequencies e.g. for data transmission systems

Abstract: The modulator has an electro-optical active crystalline substrate (1) with a single mode, double refractive optical waveguide (2). The modulator also has an electrode structure (3,4). The optical waveguide (2) runs at an acute angle (alpha) to the optical axis (c) of the crystal. An electric wave running to the electrodes (3,4) causes a coupling between the polarisation modes in the waveguide (2). A frequency shift of the optical waves in the waveguide (2) is achieved. The substrate (1) is preferably a semiconductor material.

Operating mobile terminal in mobile radio network

Abstract: The method involves using an antenna with a superimposed directional characteristic on the terminal (MS). The transmission/reception direction of the antenna during operation is determined by the position of the terminal or an object carrying the antenna. The antenna has an aperture angle of from 120 to 20 degrees. The antenna can be non-adjustably connected to the terminal housing and can take the form of a compact device with a laterally directed noise output opening and a transmission/reception direction towards the opposite side.

Method for securing data transmission in complex telecommunications and data systems

Abstract: 2.1 In securing data traffic in known systems of this type, discrepancies occur between optimum protection against unauthorised intervention, even of an internal nature, on the one hand and hindrances to use, e.g. storage problems and the protection of personal data, on the other hand. 2.2 In the method according to the invention, a mutually exclusive division of the scopes of authorisation is carried out, in which one type a) relates to the operating system and to the guaranteeing of availability and reliability, and a second type b) serves to prevent and identify unauthorised intervention and to collect associated operator data. For this purpose, two separate databases with different methods of access are formed and a session number is set up as an aid to data integration. 2.3 The invention is suitable for all types of security management systems in distributed and complex data transmission, telecommunications and data processing systems, even for commercial payment transactions.

Emergency call appts. with connection between locations and emergency call network

Abstract: The emergency call appts. has a mast (2), a call unit and a current supply. The call unit is made up of the circuitry of a mobile telephone connected in a modified form in a stable housing (1). The operating buttons (8) and the display elements (7) are arranged on the front side of the housing (1).The call unit housing is integrated in the mast (2) or is mounted on the mast (2) at head height. The telephone antenna (4) and the current supply, preferably a solar system (3), are arranged at the head of the mast (2). The housing is preferably an aluminium housing (1) with sound inlet and outlet openings on the front, over the microphone (6) and the loud speaker (5).

Call forwarding appts. for relaying call from first communication network to second remote group telephone system (GSM)

Abstract: The device forwards calls from the first network to the second network, spatially removed from the first. The second network is one of several GSM mobile radio networks. A network transition node, serving as a bridgehead (11) in the region of the first network (12) is allocated to one of the GSM networks (transition network). Call numbers of the first network (12) are allocated to the bridgehead (11) to which other call numbers of the first network (12) can be switched by call forwarding. In the bridgehead (11) the call numbers allocated to the bridgehead (11) in the first network can be allocated GSM call numbers. The bridgehead (11) is connected to a mobile exchange (15) of the transition network via signalling and data channels (14). The bridgehead (11) has the basic functions of GSM subscribers.

Encoded signal radio transmission method e.g. for local television signal

Abstract: The method involves modulating a carrier with signals of a number of digital channels. The modulated signals are received by intermediate stations which decode the signals and feed them to receivers. Signals are transmitted in at least one of the channels to the intermediate stations. These signals are not tuned to the receiver of at least one of the intermediate stations. The untuned signals are replaced in the station(s) in question by signals which are tuned to the receiver of this station. The untuned signals may be test card-type signals. The digital channels which contain the untuned signals have transmission capacity for one or more video signals and/or audio signals and/or data signals.

Transferring software engineering methods to VLSI-design: a statistical approach

Abstract: The possibilities of VLSI technology grow by a factor of 100 per decade. In parallel, design efficiency has been increased only by a factor 30 per decade, so major problems in the development of complex systems have been shifted from controlling new technologies to the management of the design process itself. Classical design methods tend to fail for VLSI circuits with increasing complexity, often due to communication problems. To avoid redesigns, the adoption of methods of neighbour discipline software engineering seems to be a good choice. This paper discusses the influence of these methods on the quality of VLSI designs in terms of errors per design and costs per error detection. Statements and experiences are based on statistical data collected during several developments of complex systems including VLSI components. >