Abstract: A method to realize synchronization in a receiver (RX), of data (DAT) sent from a transmitter (TX) to the receiver (RX), with a signal (SIG) available in the receiver (RX). The method includes the following steps:in the receiver (RX) generating trigger signals (T) from the signal (SIG) available in the receiversending the trigger signals (T) from the receiver (RX) to the transmitter (TX); andupon receipt of the trigger signals (T) by the transmitter (TX) sending the data (DAT) from the transmitter (TX) to the receiver (RX).

Abstract: A wavelength converter is disclosed having a Sagnac interferometer (NOLM, nonlinear optical loop mirror) as its essential part. In order that the wavelength converter can also be used for NRZ (nonreturn-to-zero) signals, it has a 3.times.3 coupler (2) with six ports (6-11).

Abstract: The invention concerns a method of operating a broadband link for the exchange of data (DAT) between a mobile terminal (MS) and a network-side mobile radio facility (MSC), as well as the mobile terminal (MS), the network-side mobile radio facility (MSC) and a mobile radio system. Two or more radio channels to the mobile terminal (MS) are established and assigned as subchannels (C1 to CN) to the broadband link. The data (DAT) are then transmitted via the subchannels (C1 to CN) between a terminal-side entity (ENMT) and a network-side entity (ENNET) of a communications layer (L2), where the entities (ENMT, ENNET) exchange the data (DAT) as data packets (FRDAT1, FRDAT2) in accordance with a transmission protocol, and control the distribution of the stream of data packet to the subchannels (C1 to CN) as well as its recombination. The protocol (PROT) defines and supports two or more different packet types for transportation of the data.

Abstract: A method of performing cellular digital radiocommunications in a TDMA system implemented within a network of geographical cells through which mobile stations (SM1 to SM22) travel, a base station being associated with each of the cells, a mobile station communicating via the base station that is associated with the cell in which the mobile station is located. Each each of the frames in the up transmission direction, from the mobile stations to the base station, contain at least one shared time slot (IT6) which is allocated to at least two distinct mobile stations (SM7 to SM22). For each shared time slot (IT6), the system has a list (31) of the active mobile stations, an active mobile station being a mobile station to which the shared time slot is allocated, and which satisfies at least one predetermined selection criterion.

Abstract: An electric and/or optical submarine cable arrangement which bridges the weight/strength gap that exists between armoured and unarmoured cable. A stranded armour layer (6) comprises alternate strands of steel wire (7) and polymeric filler (8). Such a cable has sufficient strength to support a section of heavy armoured cable joined to it during laying in water of a depth exceeding 2 km, but light enough that an unarmoured cable can support it in deep water.

Abstract: An optical cable has a core containing optical fibers, non-metallic peripheral reinforcements to armor the cable and a thermoplastics material outer sheath. It is fabricated by a method including successive steps of applying reinforcements to the core, extruding the sheath over the reinforcements and cooling the cable. The reinforcements are extruded onto the core as it moves through a first extruder. The combination of the core and the reinforcements is then cooled in a first cooling tank. The sheath is extruded in a second extruder downstream of the first, after which the cable is cooled in a second cooling tank downstream of the first.

Abstract: An integrated optoelectronic semiconductor component is presented, which can equally process light signals of any polarization direction. Such semiconductor components are used for digital optical telecommunications. The semiconductor component has active (A) and passive (B) waveguide sections, which comprise a number of semiconductor layers (SP) with so-called multiple quantum well structures. The semiconductor layers (SP) are deposited by a process known as selective area growth (SAG). A portion of the semiconductor layers has a lattice constant which is smaller than the lattice constant of a substrate (SUB). This creates a biaxial tensile strain in these layers. The tensile strain is optimized in the active waveguide sections (A) to attain polarization independence. Furthermore a process is described whereby such a semiconductor component can be manufactured.

Abstract: A method of synthesizing a finite impulse response digital filter includes a phase of calculating the impulse response g(t) of an analog filter the transfer function of which is defined by a predetermined bandwidth B, shape factor SF and out-band attenuation level A. The coefficients of the digital filter are extracted by sampling the resulting impulse response. The calculation phase consists in expanding the impulse response into an integer number M of Hermite functions predetermined in accordance with the shape factor SF. The coefficient extraction phase includes sampling of the expanded impulse response after the calculation phase in a time window the duration of which is dependent on the out-band attenuation level A using a sampling period At that is dependent on the bandwidth B.

Abstract: A coupling is presented for coupling two electromagnetic hollow conductors (waveguides) with different cross-sectional shapes. The coupling includes steps (S1-S3) arranged sequentially in the axial direction, having an essentially rectangular cross section and rounded corners as well as different clearances. The dimensions of all steps (S1-S3) are purposely designed so that other modes in addition to the basic mode are able to propagate therein. Because of the dimensions of coupling (3), only modes intended to conduct signals propagate in the joined waveguides, while those which are not intended to conduct signals are essentially cancelled by superposition.

Abstract: A band-pass filter written into an optical waveguide includes at least one Bragg grating creating coupling between two propagation modes. In one version the pitch of the grating is equal to the length of beating of these two modes, to create codirectional coupling for the LP01 and LP0i modes. In another version the grating couples the LP01 mode to any contradirectional radiation mode. The filter includes, at one point at least of the grating, an area in which one half-period of the grating is omitted to create a phase-shift of .pi. between the two coupled modes.

Abstract: A quadrature modulator including two mixers to which two carrier signals are applied and to each of which a modulating signal is applied, output signals of the mixers being applied to a combiner to constitute a modulated signal. A defect estimator for the modulator detects a first signal representative of the instantaneous power of the modulated signal, generates a second signal representative of a reference envelope obtained from the modulating signals, and corrects the amplitude of one of the first and second signals in accordance with the mean amplitude difference observed between this amplitude corrected signal and the other signal. A processor supplies from the observed amplitude difference between the amplitude corrected signal and the other signal, at least one signal relating to the defect.

Abstract: A power converter comprises two main switches connecting an output either to the positive rail or to the negative rail. Two freewheel diodes for maintaining the current in the load, two snubbers and an auxiliary circuit including an auxiliary inductor in series with two auxiliary switches connected between the output and a mid-point of a capacitive voltage divider supplying a median voltage. Any error of the median voltage relative to its nominal value is evaluated and the main switches are additionally commanded, depending on the direction of the error, for a time period dependent on the amplitude of the error, in order to cause an additional current in the auxiliary circuit to correct the error at least in part.

Abstract: In a multi-carrier system, the pilot carrier which is transmitted between two stations for synchronisation purposes, is re-allocated to a new frequency whenever it is disturbed by noise or a single frequency disturber in the vicinity thereof. A less noisy frequency is selected by means of a specific criterion to be fulfilled, for instance based on signal to noise ratio measurements performed for all carriers in the multi-carrier system.

Abstract: A fiber optic cable comprises a plurality of packages each made up of a plurality of optical fiber ribbons. The packages are arranged in a tight structure incorporated in a polymer resin so that the packages themselves constitute reinforcements that impart strength to the cable and prevent curvature of the optical fibers due to variations in temperature. This eliminates the need to incorporate any central and/or peripheral reinforcing member into the cable.

Abstract: A semi-automatic method of extracting a contour in a digital image using a combined active contour and starter/guide approach is based on an iterative process of deforming an active contour to obtain a current trace and extending the current trace by a straight line segment. An initial contour is entered into the image to seed the iterative process. Local analysis of the digital image at a point of the initial contour determines a first reference datum. At each iteration this analysis is carried out locally at a plurality of points around the end point of the current trace to determine, by correlation with the first datum, the orientation of the straight line segment extending the current trace.

Abstract: A low noise amplifier structure based on a Differential Difference Amplifier (DDA1) having a differential output (outp, outn) and two differential pairs of input terminals (N1, P1; N2, P2). The input signal (V.sub.IN) is applied to terminals (N2, P1) which belong to different differential pairs. In this way, none of the differential pairs receives a high input signal, and hence none of them cause unacceptable harmonic distortion. The dynamic input range is thus high. The gain of the structure is determined by a resistive circuit (R2a, R2a'; R2b, R2b') coupled to the remaining terminals (N1, P2) of the differential pairs. The common mode of these remaining terminals (N1, P2) is, independently from the output common mode, biased at the input common mode via a common mode feedback circuit (DDA2; GL1, GH1, GH3, R2a, R2a'; GL2, GH2, GH4, R2b, R2b') based on a second differential difference amplifier (DDA2).

Abstract: An electrical transmission line for conveying and limiting current by using a plurality of tubular portions made from a superconductive material. The tubular portions have a high critical temperature and are connected end-to-end by flexible, electrically conductive metal or alloy joints. A cryogenic fluid flows inside a first tube within the tubular portions. A vacuum is maintained inside a second tube around the tubular portions.

Abstract: In a method of fabricating a surface-emitting laser, to assure good electrical confinement and good flatness of the mirrors defining the resonant cavity of the laser an electrical confinement layer is formed by carrying out the following steps:forming an undercut layer,at least one growth step on the undercut layer,forming a mesa defining the shape and the location of the top mirror and exposing the undercut layer on its vertical walls, andcontrolled lateral etching of the undercut layer. Applications include the fabrication of a semiconductor laser on a III-V (e.g. InP or GaAs) substrate.

Abstract: A composite based on a superconducting oxide having a high critical temperature, characterized by the fact that it is constituted by glass and said oxide, the glass being such that its vitreous transition temperature is not greater than 750K, the volume fraction of the glass lying in the range 2% to 40%, said oxide existing in the glass in the form of crystallites having substantially the same orientation.

Abstract: The invention is drawn to organic compounds of the general formulae L--A--Z or L--A'--L' as defined in the specification. The compounds are readily crystallizable and can be used for their ferromagnetic properties.