Abstract:
The invention relates to a crosslinkable material that is active in non-linear optics, containing a polymer which carries chromophores each included in a polymer unit of formula: ##STR1## in which: T is part of the polymer chain,A is an --NO.sub.2, --CN or --C(CN).dbd.C(CN).sub.2 group,R.sub.1 is a hydrogen atom or a methyl or ethyl group,R.sub.2 is a CH.sub.2, C.sub.2 H.sub.4, C.sub.3 H.sub.6 or C.sub.4 H.sub.8 group, and:either X=Y is an azo group, F being a hydrogen atom and G being a group --C(O)--O--W or a group --C(O)--O--(CH.sub.2).sub.n --O--W, n being an integer between 2 and 6 and W being a hydrogen atom or a dimerizable group,or X=Y is an azomethine group, one of the groups F and G being a group --O--W or --R.sub.3 --O--W, R.sub.3 being a group --O--C(O)--R.sub.4 -- or --O--R.sub.4 --, where R.sub.4 is a C.sub.1 to C.sub.6 alkyl, the other of the groups F and G being a hydrogen atom and W being a hydrogen atom or a dimerizable group.
Abstract translation:本发明涉及一种在非线性光学元件中有活性的可交联材料,其含有每个包含在下式的聚合物单元中的发色团的聚合物:其中:T是聚合物链的一部分,A是 -NO 2,-CN或-C(CN)= C(CN)2基团,R 1为氢原子或甲基或乙基,R 2为CH 2,C 2 H 4,C 3 H 6或C 4 H 8基团,X = Y 是偶氮基,F是氢原子,G是基团-C(O)-OW或基团-C(O)-O-(CH 2)nOW,n是2和6之间的整数,W是 氢原子或二聚化基团,或X = Y是偶氮甲碱基,基团F和G中的一个基团为-OW或-R3-OW,R3为基团-OC(O)-R4-或-O- R4-,其中R4是C1-C6烷基,基团F和G中的另一个是氢原子,W是氢原子或二聚化基团。
Abstract:
An optical amplifier having a doped fluoride glass optical fiber and a process for producing such an amplifier. To produce the doped fluoride glass fiber amplifier which is operable to amplify a light signal (S), an optical multiplexer (4) is produced having on the one hand two silica fibres (6, 8) and on the other a fluoride glass fiber (2), whereof at least one section is doped and an optical coupling is brought about between the fluoride glass fiber and at least one other silica fibre (12, 14).
Abstract:
A process and apparatus for measuring the resemblance between sound samples incorporating a learning phase and a test phase, each having a digital acquisition and preprocessing stage, an order p acoustic analysis stage and a p.times.p covariance matrix calculating stage with respect to the resulting vector signal, the learning phase also having a reference X covariance matrix inversion stage and a stage of storing the thus obtained matrix X.sup.-1 in a dictionary, the test phase incorporating a stage of multiplying the covariance matrix of test Y with the reference matrix X.sup.-1, a stage of extracting all or part of the p eigenvalues .lambda.k of said matrix product and a calculating stage using a family of functions f, called generalized sphericity functions, so as to obtain a digital value measuring the resemblance between the considered test sample and the reference samples of the dictionary. Alternative implementations are also described, which advantageously allow the same result to be obtained without requiring the explicit calculation of eigenvalues.
Abstract:
A method for the laying out of the infrastructure of a cellular communications network, notably with mobile units, the network being of the type constituted by a plurality of broadcasting transmitters, each broadcasting on its own broadcasting cell, at least certain of the cells being adjacent and having common overlapping zones, a system of management of the network assigning a single broadcasting cell to a given mobile unit at a given time, according to a given broadcasting transmitter assigning method, the method for the laying out consisting in determining the geographical location and the technical characteristics of each of the transmitters of the network in taking account of the conditions of entry/exit and of movement of the mobile units in the overlapping zones. Thus, the coverage of the network is determined dynamically, such as it is seen by the mobile units.
Abstract:
An optical system comprising a monomode main optical fiber coupled to a phototransducer, by means of an assembly between the monomode optical fiber and the phototransducer, which assembly comprises, in succession: a piece of graded index multimode fiber, a piece of step index multimode fiber, and a microlens.
Abstract:
A method and a system of interactive access on the telephone to information elements that have already been broadcast or are being broadcast from a set of sources. For this purpose, the system has a center for the digital recording and management of radio broadcast information elements, accessible through the switched telephone network by keying in a telephone number and the time at which the information to be listened to has been broadcast.
Abstract:
A process for broadcasting conditional access programs which permits a progressive access. Scrambled program data is transmitted along with partial access checking messages and complete access checking messages such that subscribers having a partial access right may descramble portions of the scrambled data corresponding to information regarding only the identity of the conditional access programs, and subscribers having a complete access right may descramble the remainder of the scrambled data and view the conditional access programs. The conditional access programs may be television pictures, radio programs, or data broadcasts.
Abstract:
A decision feedback equalizer device and method for the block transmission of information symbols in which the received noise-affected observation samples are subjected to a whitening of the noise so as to generate whitened-noise observation samples. The current symbol is detected from earlier decided symbols and whitened-noise observation samples. Block transmission of information symbols can thus be performed over a distorting channel in an atmospheric, ionospheric or other environment towards fixed or mobile receivers.
Abstract:
A method for embodying a display cell with a counter-electrode contact pickup. Contact blocks 12 are separated from counter-electrode contacts 20 by passivation film 22. The electrodes linked between the counter-electrode and the contacts 20 are obtained by calcining the glue of the blocks so as to render them conductive by using a laser beam 30. In addition, the passivation film 22 is perforated by using the laser beam 30. This method finds particular application in the embodiment of liquid crystal display screens.
Abstract:
A method for the decoding of digital data obtained according to a convolutional coding and transmitted on a noise-ridden channel aimed at improving the methods of maximum likelihood decoding such as the Viterbi algorithm consisting in associating, with each estimation s(t) of the corresponding source digital element a(t), a weighting coefficient m(t) representing the reliability of the estimation s(t), the estimation s(t) taking account of the values of a first series of L received samples, and the weighting m(t) taking account of the values of a second series of N samples received, N being strictly greater than L. In a preferred embodiment, a second trellis is associated with the standard first decoding trellis, a trace-back being done in the second trellis on two concurrent paths, used to revise the weighting coefficients obtained at output of the first trellis.