Abstract:
L'invention concerne un procédé de codage de données d'une communication sans contact d'un transpondeur vers un lecteur par modulation de charge, sous forme d'un ensemble de motifs de modulation, chaque motif de modulation - étant une succession de niveaux de charge d'une longueur prédéfinie servant au codage physique, - ayant une durée de n périodes de porteuse (T c ), - comprenant une succession d'au moins deux niveaux de charge, - ayant une largeur d'impulsion minimale (w) correspondant à la plus courte durée d'un même niveau de charge dans le motif, et - ayant un taux de rétromodulation (t) correspondant au rapport entre le temps de rétromodulation et la durée d'un motif caractérisé en ce que - le nombre (k) de motifs est supérieur à quatre, - les largeurs d'impulsion minimale (w) d'au moins deux motifs sont différentes, et - les taux de rétromodulation (t) d'au moins deux motifs sont différents. L'invention concerne également un dispositif de mise en œuvre du procédé.
Abstract:
A communications system and protocol for a radio communications network including a number of transceiver devices. The protocol ensures that network variables to be shared by all devices are correctly received and updated by all devices. The protocol also provides for accurately detecting the transition from one time slot to another, in a given data transaction.
Abstract:
A method of transmitting "biphase" encoded digital signals comprised of the steps of receiving one of a multiplicity of input data bits, wherein each data bit is characterized by a temporal data bit length (12), a temporal bit center (T3) and a temporal state indicative of a logical 1 or 0, and generating an encoded digital baseband signal characterized by a temporal state indicate of a logical state therein the encoded digital baseband signal changes its temporal state according to whether the one input data bit changes its temporal state at a time prior to (T1 or 6) or after (T2 or 7) the temporal bit center (T3). A single sideband with this coding is generated independently by digital synthesis. Detection of the single sideband does not require re-insertion of the carrier.
Abstract:
A vehicle information system including a tag system (120B) mounted in a vehicle (100). The tag system (120B) transmits vehicle-related data acquired from the vehicle (100) to an interrogator (300B). The vehicle information system utilizes a bus (110) in the vehicle (100) with low-cost RF communications in the tag system (120B) and an interrogator (300B) to remotely access the vehicle-related data as the vehicle exits and enters a designated area. The interrogator (300B) provides the vehicle-related data acquired from the tag system (120B) to a host computer (320). The vehicle information system can use an encoding system including an encoder that Manchester encodes a data value to produce a coded data value and produces a first invalid Manchester encoded sequence as a start of frame. Also produced is a second invalid Manchester encoded sequence as an end of frame. A transmission packet is produced including the start of frame followed by the coded data value followed by the end of frame. The start of frame is a sequence of "110110" and the end of frame is a sequence of "001000".
Abstract:
Physical layer devices and related methods for determining Bit Error Rates (BERs) and correcting errors in signals received through shared transmission media of wireless local area networks are disclosed. A physical layer device is configured to identify coding violations in received signal, determine a rate of the coding violations in the signal, and estimate a BER of the signal to be equal to the determined rate of the coding violations. A physical layer device is configured to invert a half symbol immediately preceding or immediately following a coding violation based, at least in part, on signal integrities of the half symbol immediately preceding and the half symbol immediately following the coding violation to correct a bit error.
Abstract:
Dans le procédé de l'invention, les données sont intégrées dans un signal carré de fréquence F comprenant des créneaux de niveau haut (14) et de niveau bas (15), modulés par des transitions binaires (16, 17) représentatives des données puis émis à un débit binaire déterminé. Selon le procédé, on échantillonne le signal reçu à une fréquence Fe multiple de la fréquence F et on obtient une suite d'échantillons (x) dans chaque créneau (14, 15) reçu; on compte des échantillons (x) successifs de même niveau et on obtient un nombre d'échantillons (i); on compare le nombre (i) d'échantillons à un seuil (Sl) de détermination d'une transition et, s'il est inférieur audit seuil, on en déduit la présence d'une transition dans le créneau pour donc déterminer la valeur binaire de la donnée représentée par la transition. L'invention s'applique bien au télépéage de véhicule
Abstract:
The invention relates to a circuit for evaluating a digitally coded signal. Said circuit comprises a counter (4) which assigns a counter value to a level duration by means of a control logic (2), said counter value being compared with preset and lower and upper threshold values (T1, T2). At least one comparator (5) is provided for said purpose. The threshold values (T1, T2) can be doubled with a shifter (9) so that level duration having a double length such as those occurring in Manchester coded signals can also be detected. Depending on comparison results, an evaluation unit (11) provides an activating signal preferably for activating an energy-saving operating mode.
Abstract:
A method of a receiver is used for receiving an amplitude shift keyed signal provided over a multi-layered transmission from a plurality of antennas with different precoding of different symbols for the respective layers. The method comprises receiving a sequence of signal values of the signal, estimating, from the sequence of signal values, channels for the respective layers, and selecting one of a plurality of detection methods based on a difference in quality between the estimated channels. A receiver and a computer program are also disclosed.
Abstract:
Methods and apparatuses relating to balanced transmittal of data are described. In one embodiment, an apparatus includes an encoder to encode input data into at least one data group with each data group having an equal number of a first level signal and a second, lower level signal to transmit the at least one data group over single conductors in parallel, and a decoder to decode the at least one data group into output data. In another embodiment, a method includes encoding input data with an encoder into at least one data group with each data group having an equal number of a first level signal and a second, lower level signal to transmit the at least one data group over single conductors in parallel, and decoding the at least one data group into output data with a decoder.