Abstract: 2-amino-5-nitropyridinium salts are provided which are usable in non-linear and electrooptics.

Abstract: A liquid crystal display screen including a substrate with conductive addressing columns and conductive blocks, each including a block lengthening piece, a layer of semiconductive material followed by a layer of nonconductive material formed on the addressing columns and conductive blocks, and conductive addressing lines formed on the nonconductive material and each overlapping a block lengthening piece. The block lengthening pieces, the conductive addressing columns, and the conductive addressing lines form addressing transistors. Also, capacitive lines are formed on the nonconductive material and overlap the conductive blocks such that the conductive blocks, the semiconductive material, the nonconductive material, and the capacitive lines form storage capacitors.

Abstract: A method and apparatus for throughput compression for use in a videophone camera wherein an array of photosensitive cells is divided into odd and even lines and the cells of these cells are interlaced with each other and then the interlaced lines are coupled together such that during a first time interval the electric charges stored in the cells of the even lines are transferred to a plurality of first storage cells, then transferred to a plurality of corresponding second storage cells during a succeeding time interval and finally added in the second storage cells to the electrical charges in the corresponding cells of the odd lines of the cell array during a third time interval.

Abstract: An equipment embodying the invention is designed for bit-level quality check of a digital link in the presence of real traffic. The equipment complies with CCITT recommendations and comprises two checking stations (SP, SS) respectively located at two ends of the digital link (LT) and connected to one another by a service link (LS). First and second check information relating respectively to groups of transmitted frames (MTn.sub.p) and to groups of received frames (MTn.sub.s) are calculated in the stations and comparisons are made in order to detect the transmission errors. The check informations and the frame groups concerned by the transmission errors are transmitted from one station to the other via the service link. Processing circuits are distributed among the stations thereby processing the frame groups concerned by the transmission errors, i.e., analyzing at bit level the errors in the erroneous frames and deriving statistical information and recordings relating to said errors.

Abstract: Inside a range of action defined by a station, the station is able to generate therein an enquiry message followed by a silence zone. The station then selectively analyzes the respective contents of a plurality of disjoint time intervals from this silence zone. In the event of obtaining in one of these time intervals, chosen randomly by a single portable object, a content identified as a specified response message associated with this portable object, the station generates a selection message intended for this portable object, which, on reception of this selection message, generates in its turn an acknowledgement message. There follows provision for a phase of transactional communication between the selected portable object and the station.

Abstract: The device comprises an echo cancelling circuit receiving a first signal and a second signal and a real echo between channels for producing a third signal containing the second signal and a difference between the real echo and the estimated echo. Detectors detect the echo difference and the second signal in the third signal when the level of the third signal exceeds a predetermined threshold. Circuits gain-control the adaptation in the adaptive filtration of the echo cancelling circuit in such a way as to modify the adaptation gain when the second signal is not detected and to prohibit all filtration modifications as long as the second signal is detected. For instance, for an acoustic echo in a telephone set, the echo is not processed when the third signal contains a local speech signal as second signal.

Abstract: A method and device are provided for encoding-decoding an HD digital television signal into a narrow band encoded signal. The HD digital television signal is representative of high definition images sampled at a frequency f1, and the narrow band encoded signal corresponds to a narrow band signal sampled at f2, wherein f2<f1. Narrow band encoding is achieved by horizontal compression by decimation of the image lines of the HD digital television signal so as to bring the number N1 of useful pixels per image line to a value N2=.alpha. of the sampling frequencies, so as to thus form an encoded signal representative of an image line and obtain reduced format high definition images. A narrow band encoded signal representative of digital television signals can thus be broadcast over an HD-MAC NB type channel.

Abstract: Control protective circuit, in particular of liquid crystal display screen. The protective circuit includes three transistors making possible the transfer of the voltage to output pin, the resetting of middle point and the resetting of the output. Application to the control of liquid crystal display screens.

Abstract: A method for the automatic analysis of signals by segmentation and classification. To segment the signal, the method is carried out repeatedly by aggregating samples and merging adjacent pulses. Once segmentation has been obtained, classification is carried out. The method has particular application to the analysis of signals with a physiological origin.

Abstract: The method is founded on the GUAZZO algorithm and is adaptive as it does not require any prior statistical knowledge of source of message to be coded. The message is comprised of a sequence of symbols of the source which are represented by the indication of the direction "0" or "1" chosen at each node of a binary tree. According to the invention, the adaptiveness is obtained by associating with each node two finite-sized counters that count the "0"s and "1"s according to the routing of the tree. The contents of these counters enable the conditional probability of each of the elements "0" and "1" to be estimated at the node.

Abstract: A circuit for controlling the lines of a display screen and including a t means with a single output is disclosed. The test means includes a single test control line (LCT), a single test output line (LST) and a plurality of sample holders (CEBj) and associated gates (Pj) and switches (Ij). The output voltage of the sample holders is transmitted onto a test output block (ST).

Abstract: Method for obtaining an organic polycrystalline material having in particular electro-optical properties, said material obtained and an electro-optical modulator comprising said material. This method includes a stage (1) for preparing a powder having a size grading of 500 to 800 nm of an organic compound having a delocalized system of .pi. electrons and presenting a non-centrosymmetrical crystalline structure, as well as intramolecular load transfer groupings, a stage (2) for drying the powder under vacuum, a stage (3) for pre-pressing the powder under vacuum, and a hot stage (5) for the uniaxial compression of the dried powder under vacuum. This method enables polycrystalline materials to be obtained, said materials comprising elongated monocrystalline grains orientated according to a given direction.

Abstract: A video path receives the signal to be processed and a reference path receives a reference voltage, with both paths subjecting their respective signals to logarithmic amplification having the same characteristics. These two paths are combined in a summing circuit giving gains respectively of gamma and of one minus gamma. The output from the summing circuit is applied to an exponential amplifier which is followed by a buffer to provide the corrected output signal. By an appropriate adjustment of resistances in the summing stage and also by means of switching, it is possible to perform gamma correction over the range about 0.2 to about 5, and it is possible to perform such correction on very wideband analog signals.

Abstract: A process for exchange of rights between microprocessor cards, wherein multiple keys (K1, K2, . . . ) and varied keys (Ka5, Kb3) are used. A card to be debited calculates a voucher with varied key (Ka5) that the card to be credited reconstitutes. The process has application to electronic payment.

Abstract: A movement estimation method and system are disclosed for high definition digital television frames. The movement is estimated for a current block Bc of the even fields T.sub.2k, 2r-1 of the uneven frames with which n movement vectors are associated, with the current block Bc of the even fields T.sub.2k, 2r of the even frames there is associated, by relative addressing, a movement vector with respect to s vectors of the preceding frame I.sub.2r-1 surrounding the frame B'c of the current block Bc. The s vectors are chosen by eliminating the vector redundancies among the n vectors. The invention is applicable to broadcasting and transmission of digital television signals by HD-MAC or HD-MAC NB narrow band channel.

Abstract: Method for producing a display screen with a matrix of transistors provided with an optical mask. This method consists of depositing on a substrate (100) a layer of black polyimide (102) absorbing the visible light and followed by a layer of photosensitive resin, of insolating the resin through a mask masking the channels of the transistors to be embodied, of eliminating the zones insolated with the resin and the sub-adjacent zones of the polyimide, of depositing an ITO layer (106) on the unit, of eliminating the rest of the resin and the ITO surmounting said resin so as to form the drains/sources of the transistors, of successively depositing a layer of hydrogenated amorphous silicon (110), a layer of silicon nitride (112) and a layer of aluminium (114), then of photoengraving the stack of these layers so as to form the gate of the transistors, and finally to render passive the unit with a layer of silicon (116).

Abstract: Process for optical transmission by wavelength shifting and corresponding system. According to the invention, a wavelength hop corresponding to a mode hop of the laser is performed. The laser (20) is supplied by two currents, which fix the emission wavelengths (.lambda.1, .lambda.2).

Abstract: The method includes only two masking levels. During the second masking, capacitative lines (LC) (dedicated or merged with the addressing lines) are defined which overlap the pixels so as to form the storage capacitors (Cs).Application for display on flat liquid crystal screens.

Abstract: A process for optical transmission by self-heterodyning and a transmission system with a switching matrix using the process. The process consists in transmitting optical signals to one or more receivers of N, from optical transmission means including an optical signal emitting device for modulation by frequency transposition, and an optical fiber connection. Also included in the process is the transmission a given signal on one or more carrier frequencies respectively to one or more receivers, the obtaining of the carrier frequency or frequencies by transposition of an emission frequency by one or more modulation frequencies which are distinct and can be selected as a function of the receiver or receivers, and the transmission of the emission frequency signal on the same optical connection.

Abstract: A device for allowing fee paying subscribers access to television or radio programs includes a keyboard unit for requesting messages concerning the programs. Information describing the program fees and account status is contained in a subscriber held security processor such as a smart card. As a function of the content of the requests a mechanism converts the information contained in the security processor into intelligible messages as a function of complementary information transmitted regularly within television and/or radio signals.