Abstract: A sometimes positive and sometimes negative frequency deviation is associated to a given logic value. The deviation is positive during a certain period of time and then negative, the respective periods being determined so that the cumulated sums of the positive and negative deviation periods are practically equal. A device comprises to this effect an analyzer element for analyzing the asynchronous NRZ signal, having an analog integrator (1, 2) for measuring time, which actuates a switch (3) for selecting a control voltage (MOD) from three voltages. This analyzer element comprises a D-flipflop (2) to whose clock input (CP) is fed the asynchronous NRZ signal, with a resistance-capacitance feedback (4, 1) between its output Q and its input D, and with means (3) for connecting the output {overscore (Q)} of the flipflop (2) to its input D when the NRZ signal has a given logic level.

Abstract: A communication bus system is disclosed. More particularly, the communication bus system includes requesting stations that can issue request packets via a bus and an execution station. The execution station receives the request packets and executes commands modifying the same aspect of a state of the execution station in response to request packets from different stations. The execution station keeps information concerning execution of commands which were last executed in response to request packets for all the different requesting stations. The requesting stations can read this information to determine whether the commands corresponding to their packets are executed, even when other requesting stations are also issuing request packets. Preferably, the execution station shows each requesting station only the information about the execution of commands executed to its own request packets.

Abstract: A method is disclosed for communication between a plurality of stations. The method includes selecting a master station, which becomes responsible for building and broadcasting at least one service information table (such as the tables defined in MPEG or DVB), and communicates with the (N−1) to the other stations, known as slave stations, in a limited number of situations corresponding to modifications of the content of the tables and according to a specific table management, where the master station is always in one of three states that are either a waiting state, or a building state, or a transferring state, and specific communication rules for the slave stations and the master station.

Abstract: A device having alternative intercommunication formats, and an automated method of selecting the appropriate format to use, in dependence upon the ability of the device to which it is interconnected to utilize this format. Many devices utilize standard analog formats, such as NTSC, PAL, SECAM, and others, to communicate with other devices; many of these devices utilize digital formats, such as MPEG and others, for internal processing or storage. By appending a supplemental signal to the analog signal, the ability of the device to use a digital format can be communicated to the device to which it is interconnected. By communicating their capabilities, devices which have the ability to utilize the same digital format can automatically switch to this digital format for intercommunication, thereby avoiding the signal degradations typically associated with conversions to and from an analog form.

Abstract: An audio equivalent input signal is divided into a sequence of overlapping or adjacent signal segments. A lengthened signal is synthesized by systematically maintaining or repeating respective signal segments of the sequence of segments. Repeating non-periodic segments, such as a voiceless part of a speech signal or noise in music, results in audible artefacts. The introduced periodicity is broken by dividing a signal section originating from one non-periodic source signal segment into a second sequence of signal segments with at least one of the signal segments having a duration not equal to a duration of the source signal segment and not equal to a multiple of the duration of the source signal segment. Signal segments of the second sequence are shuffled.

Abstract: A system, like a video on demand server, retrieves blocks of data from a storage medium 100 and supplies the data to users in the form of at maximum nmax data streams. Upon creation, a data stream is in a new state in which no sufficient data is present for consumption by a user, whereas a user may consume data for a data stream in an active state. A scheduler 170 repeatedly selects a group of data streams for which a data block of a predetermined size needs to be read and causes a reader 180 to read the data in one sweep and to store the read data in buffers 125. The group is formed by active data streams whose associated buffers 125 have room for storing the data block. The scheduler 170 variably determines the size of the data block for each next sweeping operation through an expression that, with respect to a number of data streams, is substantially based on an actual number nact of active data streams instead of nmax.

Abstract: The invention relates to a method of controlling access of messages contained, for example, in ATM cells, to a network (10). The cells transmitted by a source (11) are classified into n adjacent groups depending on the value of the instantaneous rate associated to each of the cells. For each cell (Ci) transmitted by the source (11) and which requests access to the network (10), a switch (122) only authorizes this access if in a global token reserve allocated per unit of time and distributed per group as a function of the number of cells each group contains, one token is still available for the group to which the cell (Ci) belongs or, if there is no such token, for a group of instantaneous rates which have higher values. This process thus establishes a priority for the slowest cells and does not allow cells occurring in bursts suddenly to disturb the network.

Abstract: An authentication system is disclosed that includes at least one station and a host. Each station having a memory for storing a plurality of authentication items. An authentication control element, such as a key, is constructed from a part of the authentication items which is selected for each message. An authenticator authenticates the message substantially under the control of the authentication control element constructed for the message. The authenticated message is sent to the host. The host having a memory for storing the authentication items of each station. The authentication control element is determined from the received authenticated message. A verifier is used for, under control of the authentication control element, verifying the authenticity of the received message.

Abstract: For translating a word-organized source text into a word-organized target text through mapping of source words on target words, both a translation model and a language model are used. In particular, alignment probabilities are ascertained between various source word & target word pairs, whilst preemptively assuming that alignment between such word pairs is monotonous through at least substantial substrings of a particular sentence. This is done by evaluating incrementally statistical translation performance of various target word strings, deciding on an optimum target word string, and outputting the latter.

Abstract: A method of operating a wireless network comprising a plurality of public wireless terminals and private wireless terminals, and optionally a base station uses a transmission frame including a control section which may schedule encrypted communication between private wireless terminals and unencrypted communication between public wireless terminals and between public and private wireless terminals. Wireless terminals may join the network as private or public terminals.

Abstract: Speech is received as a sequence of segments that are coded according to an LPC principle. The segments are reproduced for concatenated read-out in audio reproduction, by exciting an all-pole filter with recurrent signals in case of voiced speech and by white noise in case of unvoiced speech. In particular, the recurrent signals are globally represented as an accumulated series of periodic signals on the basis of mutually overlapping time windows. The recurrent signals are supplemented by noise for filtering through an amended LPC filter derived from the original LPC-filter by using information of pitch and formants, and of a voiced-unvoiced dichotomy. The filter is determined as depending on at least a subset of the four quantities Global Noise Scaling, Pitch Dependent Noise Scaling, Amplitude Dependent Noise Scaling, and Inter-Formant Noise Scaling.

Abstract: In a receiver for digital symbols, an input signal received by a tuner is passed via a SAW filter and a controllable amplifier to an input of a demodulator. The output signals (I,Q) of the demodulator are passed via controllable amplifiers to analog to digital converters. In order to avoid the use of a feedback signal from the digital part of the receiver to the analog part it is proposed to use first control means for controlling the output signal of the demodulator and second control means for controlling the output signal of the analog to digital converters. An additional advantage is that both control means can be optimized for their respective environments.

Abstract: An advanced telecommunications system is provided for the recognizing of spoken commands over a cellular telephone, satellite telephone, or personal communications network. In the cellular application, for example, a Speech Recognition System interconnects either internally with or as an external peripheral to a cellular telecommunications switch. The Speech Recognition System includes an administrative subsystem, a call processing subsystem, a speaker-dependent recognition subsystem, a speaker-independent recognition subsystem, and a data storage subsystem. The Speech Recognition System also allows for increased efficiency in the cellular telephone network by integrating with the switch or switches as a shared resource. The administrative subsystem of the Speech Recognition System is used to keep statistical logs of pertinent call information. Pre-recorded instructional messages are stored in the memory of the call processing subsystem for instructing a user on his or her progress in using the system.

Abstract: A controlled current source is disclosed which receives a control signal and supplies a current at an output. The current source includes a power module having a plurality of parallel-arranged power transistors, whose collectors are jointly connected to the output of the current source, a control module to receive the control signal, and an output to supply a signal enabling the power transistors to be turned on, wherein, the emitters of the power transistors are jointly connected to the output of the control module, the output for supplying a current whose value depends on the value of the control signal, the bases of the power transistors being permanently subjected to a voltage of a predetermined value enabling the power transistors to be rendered potentially conducting. By pre-charging the parasitic capacitances of the power transistors, the transistors are turned on at an accelerated rate.

Abstract: In a public key cryptosystem employing the El-Gamal algorithm, secret fresh random numbers are generated at a server and private keys of users, as encrypted with a symmetric algorithm by using individual user identifying keys determined by hashing the users' respective passphrases or biometric information (fingerprint, voiceprint, retina scan, or face scan) are maintained in a store accessible to the server, and the fresh random numbers and encrypted private keys are transmitted to the user equipment when needed via a network which is not secure. In order to prevent an attacker from discovering the random numbers or employing formerly used random numbers in a block replay attack, an interchange in the nature of a challenge response protocol is employed which passes at least one secret fresh random number from the server to the user equipment while also authenticating the user to the server.

Abstract: The invention relates to a predistortion circuit for an analog signal in a video communication network. In one embodiment the circuit according to the invention includes a primary branch connecting an input to an output, a delay circuit for delaying a signal in the primary branch, a first coupler/shunting device which samples a fraction of the input signal, a secondary branch connected to the shunting output of the coupler/shunting device, the secondary branch including a second-harmonic generator, and a second coupler/shunting device which receives the output signal from the secondary branch and adds it to the signal at the output of the primary branch. The circuit according to the invention makes possible a symmetrical filter with improved performance characteristics and low manufacturing cost.

Abstract: In a system 100, such as a video-on-demand-server, a reader 180 reads data from a storage medium 110 and stores the read data in buffers 125. The data is supplied from the buffers 125 to users 130 for consumption in the form of a plurality of data streams. The data streams may be fixed rate or variable rate with an identical maximum consumption rate of R.sub.max data elements per second. The reader 180 is controlled by a scheduler 170. The scheduler 170 divides a predetermined period of t.sub.cycle seconds, wherein for each active data stream at least R.sub.max *t.sub.cycle data elements can be read from the storage medium, into n successive time intervals, each of t.sub.interval seconds. For each data stream a corresponding buffer 125 is reserved for storing at least R.sub.max *(n+1)*t.sub.interval data elements. The data is read from the storage medium 110 by repeatedly sweeping the storage medium 110 for a group of data streams.

Abstract: A method for synchronizing a cycle master node to a cycle slave node, including the steps of utilizing logic circuitry in the cycle slave node to determine a timer offset value, in response to the cycle slave node receiving synchronization information, transmitting the timer offset value to the cycle master node, and, utilizing logic circuitry in the cycle master node to adjust a value of a cycle master node cycle timer on the basis of the timer offset value. The synchronization information is preferably a cycle reset signal that is asserted at a prescribed rate which is a multiple of one cycle of the cycle slave node cycle timer. The cycle master node and the cycle slave node can advantageously be included in a first network or sub-network and the cycle reset signal can be supplied by a second network or sub-network which is external to the first network or sub-network.

Abstract: In speech recognition, a reliability measure can be determined by using various sentence hypotheses with a decreasing acoustic similarity. However, if a databank inquiry is to be derived from such a speech signal, often only individual words or even a single word from the utterance are required as data for such a databank access. Such a data, for example, the time, may be contained in the speech utterance in various ways. In accordance with the invention, a reliability measure for such a data rather than for a given word is determined, in which the same data may be constituted by various words. Thus, these various words are treated equally for determining the reliability measure.

Abstract: A method by which video compression parameters of different video streams are changed to optimize overall bandwidth utilization according to rules related to the varying interactions among group members. Different video streams are allocated different portions of the overall bandwidth based on a priority scheme. The priority scheme is based upon group dynamics. A controller (central or distributed) receives a group dynamics monitoring signal which monitors the various activities of group members. The controller (central or distributed) uses the network congestion control feedback signal and the priorities assigned to the different video streams to send feedback signals to the different video transmitters requesting the transmitters to adhere to, increase, or decrease their video data rates by changing parameters controlling the video encoding process.