Abstract: A method of fighting interference in a frequency-hopping communication system is disclosed. The system has at least one main sensor and one or more auxiliary sensors. According to at least one embodiment, frequency-hopping signals are received. The frequency-hopping signals are arranged to include useful bands and one or more guard bands inserted between the useful bands, and a ratio of the useful bands to the guard bands being chosen according to a predetermined value of probability of interference interception. Signals of the inserted guard bands having a signal level greater than a predetermined threshold are selected. A set of spatial-filtering weightings are calculated according to a correlation matrix of noise plus jammers alone on the signals selected. Baseband signals of the received frequency-hopping signals are filtered by the set of the calculated spatial-filtering weightings.

Abstract: Method for measuring certain parameters of the impulse response of a propagation channel involving emitters and reflectors that are fixed or mobile, so as to detect and determine the parameters regarding the position and kinematics of these emitters and reflectors, or to auto-locate the reception system implementing the invention, in a system comprising N sensors receiving signals from said emitters or from the reflection on said reflectors, and comprising at least the following steps: determination of an ambiguity function which couples the spatial analysis and the delay-distance/Doppler-kinematic analysis, determination of at least one sufficient statistic C(l, m, K) corresponding to the correlation between the known signal s(kTe) corresponding to the complex envelope of the signal emitted and the output of a filter w(l,m) where l corresponds to a temporal assumption (delay-distance, temporal ramp, etc.) and m to a frequency assumption (Dopper-kinematic, Doppler ramp, etc.

Abstract: Method of high-resolution direction finding to an arbitrary even order, 2q (q>2), for an array comprising N narrowband antennas each receiving the contribution from P sources characterized in that the algebraic properties of a matrix of cumulants of order 2q, C2q,x(l), whose coefficients are the circular cumulants of order 2q, Cum[xi1(t), . . . , xig(t), xiq+1(t)*, . . . , xi2q(t)*], of the observations received on each antenna, for cumulant rankings indexed by l, are utilized to define a signal subspace and a noise subspace.

Abstract: A method of synchronizing a substantially rectilinear signal being propagated through an unknown channel, in the presence of unknown substantially rectilinear interferences, received by an array of N sensors, in which a known training sequence s(nT) is used comprising K symbols and sampled at the symbol rate T (s(nT), 0?n?{tilde over (K)}1), characterized in that, based on observations x((n+l/p)T) over the duration of the training sequence, where p=T/Te is an integer and Te the sampling period, a virtual observation vector X((n+l/p)T)=[x((n+l/p)T)T, x((n+l/p)T)†]T is defined, as well as a decision criterion or decision statistic taking into account the second-order non-circular nature of the interferences, by using the first and second correlation matrices of the virtual observation vector X((n+l/p)T).

Abstract: A bipolar transistor with very high dynamic performance, usable in an integrated circuit. The bipolar transistor has a single-crystal silicon emitter region with a thickness smaller than 50 nm. The base of the bipolar transistor is made of an SiGe alloy.

Abstract: A method for fighting interference in a communication system is disclosed where the links are of frequency-hopping type. The signal has several frequency time slots. The system has at least one main sensor and one or more auxiliary sensors, one or more guard band are inserted between the useful bands of the frequency-hopping signal. The total area of the inserted guard bands is chosen so as to satisfy a chosen value of probability of interference interception. The signals of the inserted guard bands are selected whose level is greater than a given threshold. A set of spatial-filtering weightings are determined, for each time slot of the signal, by taking account of the correlation matrix of the noise plus jammers alone on the signals selected. The baseband signals of the assemblage of extended blocks are filtered by the set of calculated weightings of the time slot so as to generate extended blocks devoid of interference.

Abstract: A bipolar transistor having a base region resting by its lower surface on a collector region and surrounded with a first insulating layer, a base contact conductive region in contact with an external upper peripheral region of the base region, a second insulating region in contact with an intermediary upper peripheral region of the base region, an emitter region in contact with the central portion of the base region. The level of the central portion is higher than the level of the intermediary portion.

Abstract: The invention relates to an anti-fog coating for a surface of a substrate comprising: a first polymer layer resulting from covalently bonding a polyanhydride polymer to said surface; and a second polymer layer resulting from covalently bonding a polymer selected from the group consisting of polyvinyl alcohol, partially hydrolyzed polyester, polyether and cellulose derivative; said surface having nucleophilic groups. A substrate having an anti-fog coating, as well as a process for preparing said anti-fog coating to the surface of a substrate is also provided.

Abstract: An antenna processing method for centered or potentially non-centered cyclostationary signals, comprises at least one step in which one or more nth order estimators are obtained from r-order statistics, with r=1 to n?1, and for one or more values of r, it comprises a step for the correction of the estimator by means of r-order detected cyclic frequencies. The method can be applied to the separation of the emitter sources of the signals received by using the estimator or estimators.

Abstract: Method of high-resolution direction finding to an arbitrary even order, 2q (q>2), for an array comprising N narrowband antennas each receiving the contribution from P sources characterized in that the algebraic properties of a matrix of cumulants of order 2q, C2q,x(l), whose coefficients are the circular cumulants of order 2q, Cum[xi1(t), . . . , xiq(t), xiq+1(t)*, . . . , xi2q(t)*], of the observations received on each antenna, for cumulant rankings indexed by l, are utilized to define a signal subspace and a noise subspace.

Abstract: A method of synchronizing a substantially rectilinear signal being propagated through an unknown channel, in the presence of unknown substantially rectilinear interferences, received by an array of N sensors, in which a known training sequence s(nT) is used comprising K symbols and sampled at the symbol rate T (s(nT), 0?n?{tilde over (K)}1), characterized in that, based on observations x((n+l/p)T) over the duration of the training sequence, where p=T/Te is an integer and Te the sampling period, a virtual observation vector X((n+l/p)T)=[x((n+l/p)T)T, x((n+l/p)T)†]T is defined, as well as a decision criterion or decision statistic taking into account the second-order non-circular nature of the interferences, by using the first and second correlation matrices of the virtual observation vector X((n+l/p)T).

Abstract: A method for the verification of anti-jamming in a communications system comprises several sensors or adaptive antennas, comprising at least the following steps: estimating the mean power ?;^y of the output of the communications system, estimating the respective power values Pu or P?u, of a station u, the antenna noise Pa or P?a, the thermal noise PT, or P?T, estimating at least one of the following ratios: J tot ? / ? S tot = ( ? p = 1 P ? P p ) ? / ? ( ? u = 1 U ? P u ) J tot ? / ? S u = ( ? p = 1 P ? P p ) ? / ? P u J u ? / ? S u = ( ? p = 1 P ? P pu ) ? / ? P u comparing at least one of the three ratios with a threshold value.

Abstract: A method for the fourth-order, blind identification of at least two sources in a system comprising a number of sources P and a number N or reception sensors receiving the observations, said sources having different tri-spectra. The method comprises at least the following steps: a step for the fourth-order whitening of the observations received on the reception sensors in order to orthonormalize the direction vectors of the sources in the matrices of quadricovariance of the observations used; a step for the joint diagonalizing of several whitened matrices of quadricovariance in order to identify the spatial signatures of the sources. Application to a communication network. FIG. 3 to be published.

Abstract: Blind or partially blind process to determine characteristic space-time parameters of a propagation channel in a system comprising at least one reception sensor receiving a signal y(t). It comprises at least one step in which the specular type structure of the channel is used and a step for the joint determination of parameters such as antenna vectors (a) and/or time vectors (?) starting from second order statistics of the received signals. Application for monitoring the spectrum of a propagation channel for positioning purposes starting from one or several HF stations or for standard communication links with equalization or positioning or spatial filtering.

Abstract: A method forms a bipolar transistor in a semiconductor substrate of a first conductivity type. The method includes: forming on the substrate a single-crystal silicon-germanium layer; forming a heavily-doped single-crystal silicon layer of a second conductivity type; forming a silicon oxide layer; opening a window in the silicon oxide and silicon layers; forming on the walls of the window a silicon nitride spacer; removing the silicon-germanium layer from the bottom of the window; forming in the cavity resulting from the previous removal a heavily-doped single-crystal semiconductor layer of the second conductivity type; and forming in said window the emitter of the transistor.

Abstract: A bipolar transistor having a base region resting by its lower surface on a collector region and surrounded with a first insulating layer, a base contact conductive region in contact with an external upper peripheral region of the base region, a second insulating region in contact with an intermediary upper peripheral region of the base region, an emitter region in contact with the central portion of the base region. The level of the central portion is higher than the level of the intermediary portion.

Abstract: A bipolar transistor with very high dynamic performance, usable in an integrated circuit. The bipolar transistor has a single-crystal silicon emitter region with a thickness smaller than 50 nm. The base of the bipolar transistor is made of an SiGe alloy.

Abstract: A bipolar transistor with very high dynamic performance, usable in an integrated circuit. The bipolar transistor has a single-crystal silicon emitter region with a thickness smaller than 50 nm. The base of the bipolar transistor is made of an SiGe alloy.

Abstract: A device and method for the calibration and equalization of reception chains of an antenna processing system comprises several RF chains, each associated with a radiating element, a set of sensors Ci formed out of the outputs of the preceding RF chains, a channel for the injection of a calibration signal, means to couple the calibration signal to the sensor signals and several reception-digitization chains. The device comprises at least one processor adapted to managing all the devices; a means used to adjust the value of the gain of an RF chain to a minimum value Gmin; a means for deflecting the sensors, adapted to minimizing their directivity toward the interference sources; a means adapted to adjusting the level of the injected calibration signal ST relative to the signal of the sensors, an RF chain having a gain adjusted to a minimum value Gmin.

Abstract: A method for the blind identification of sources within a system having P sources and N receivers comprises at least one step for the identification of the matrix of the direction vectors of the sources from the information proper to the direction vectors ap of the sources contained redundantly in the m=2q order circular statistics of the vector of the observations received by the N receivers. Application to a communications network.