Abstract: In a radio communication system, in particular a mobile communication system, variable-rate information flows originating from different sources (CV1, CS1; CV2, CS2) and relative to a same communication are transmitted on a same radio channel. Each mobile station (M1 . . . Mh) and the fixed part (B1 . . . Bn; RNC) of the system comprise a unit for the control of the variable-rate transmission, which dynamically allocates the available bits to the different streams by taking into account the needs of the sources (CV1, CS1; CV2, CS2), the conditions of the channel (6) and the system occupancy. (FIG. 1).

Abstract: Apparatus for measuring the effective refractive index in optical fibers, in which a source sends light radiation, the wavelength of which can be varied within a predetermined interval, into a fiber span, and a detector collects the radiation intensity of the radiation collected by the detector as the wavelength varies, in order to determine the oscillation period of the fiber transmittance or reflectivity and to obtain the effective refractive index from such period.

Abstract: The arithmetic-logic unit has elementary cells performing logic addition, one for each pair of operand bits, which are particularly optimized as far as carry propogation speed is concerned and are controlled by an auxiliary fast logic allowing their performance to be extended to the other operations. The unit also has a control signal generating circuit, subdivided into a first part (DEC1), near the elementary cell of least significant position, which generates an operation selecting signal for all the cells, and into a second part (DEC2), near the elementary cell of most significant position, which generates control signals for the auxiliary logic of each elementary cell.

Abstract: The circuit consists of two parallel branches which perform multiplication and accumulation operations for the even and odd lines of the transform coefficient matrix. Each branch includes: an input circuit (SEM1, SOT1) whereby the contributions of the opposing index columns of the matrix may be added; a multiplication circuit (ERM, ORM) which performs multiplication operations for each matrix column by an addition and shifting operation for each matrix coefficient; and an accumulation circuit for the intermediate products of each matrix column.

Abstract: An optical switching system, wherein the input channels carrying packetized data are switched one-by-one at high bit rate to output channels through an optical switching network. The packets of a generic input channel are time compressed, converted into optical signals and, at suitable instants, sent to an optical switching network to be switched to the desired output channel, they are then reconverted into electrical signals and expanded to their original duration. A centralized processor controls the channel switching through the switching network by means of a driving circuit.

Abstract: A method of manufacturing dichroic antenna structures, which makes use of a projector mounted on the mobile arm of a computer-controlled machine to project the shape of selective antenna elements on the surface of an insulating layer, clad with a metallic layer covered in turn with a photographic emulsion. Development and chemical etching of the excess conductive parts are then carried out.

Abstract: A circuit for automatically controlling the gain-bandwidth product of operation amplifiers, where gain-bandwidth product (G*B) of one of the amplifiers placed on the same chip as the amplifiers to be controlled is measured and the resulting signal is used to control through a bias circuit the gain-bandwidth products of all the amplifiers, the value of these products being presettable through the frequency of a control signal sent to the circuit input. The reference amplifier is highly compensated for and placed in the configuration of voltage follower.

Abstract: The method consists of diffusing a doping compound in the region of a fluorozirconate glass support, wherein the optical guide is to be fabricated. The remaining regions are suitably masked to avoid any possible ionic exchange.

Abstract: An integrated circuit selectively programmable to form an active filter without external circuit components, the integrated circuit having 2.sup.m amplifying modules where m is an integer between 2 and 4, inclusive, p resistive matrices where p is 1 when m is other than 4 and is 2 when m=4, and a bias circuit, r of the amplifying modules being positioned in a first column separated from a second column of r amplifying modules by a respective one of the resistive matrices, where r=4 when m is other than 2 and r=2 when m=2, the second column of amplifying modules being separated from a third column of 4 amplifying modules when m=4 by a second of the resistive matrices.

Abstract: This method provides a filtering of digital samples of speech signal by a linear-prediction inverse filter, whose coefficients are chosen out of a codebook of quantized filter coefficient vectors, obtaining a residual signal subdivided into vectors. The weighted mean-square error made in quantizing said vectors with quantized residual vectors contained in a codebook and forming excitation waveforms is computed.The coding signal for each block of samples consists of the coefficient vector index chosen for the inverse filter as well as of the indices of the vectors of the excitation waveforms which have generated minimum weighted mean-square error. During the decoding phase, a synthesis filter, having the same coefficients as chosen for the inverse filter, is excited by quantized-residual vectors chosen during the coding phase (FIGS. 1, 2).

Abstract: Mode field radius in single-mode optical fibers is measured by the modulation of an optical beam by means of a spatial filter with radial-distribution of transmittivity of Gaussian type. Modulated beam intensity is measured in correspondence with the beam axis for different widths of the Gaussian curve, and the mode field radius is derived from both such intensity values and a parameter dependent on the Gaussian width.

Abstract: A method of making optical performs from which optical fibers are drawn after collapsing of the preform, which comprises depositing by a vapor-phase reaction a plurality of layers on the inner surface of a support tube and controlling the temperature profile around the perimeter of the support so that the thickness of the deposit varies between at least one maximum and at least one minimum. Upon collapse of the support this gives rise to a core having a noncircular cross section.

Abstract: The method allows the production of silica and dopant with reactions among gaseous chemical compounds. The optical fibers produced do not present dip and exhibit low attenuation. Carbon dioxide is used as the oxidizer and organometallic aluminum compounds are used to obtain the dopant; silica is obtained from organometallic silicon compounds or silicon tetrachloride.

Abstract: The method provides the use, for the determination of the estimation echo-channel pulse response, of digital filtering techniques of the transversal adaptive type, and the subdivision of the pulse-response of the equivalent echo channel into three intervals, the second of which consists of the significant portion of the pulse response and is determined by the iterative search for the value and the position of the coefficient of maximum absolute value; the first interval corresponds to a pure delay and the third corresponds to the contribution given by the lowest frequencies of the base band. To copy the echo-signal, there are only considered the pulse-response coefficients whose indexes are comprised in the second interval, and the samples of the signals to be copied belonging to preceding sampling instants, whose indexes are also comprised in the second interval.

Abstract: Method and device for realtime measurement of the state of polarization at a quasi-monochromatic light beam. Two quasi-monochromatic radiations with slightly different optical frequencies are generated. A radiation is converted into a 45.degree. linearly polarized radiation, while the other presents the polarization state imposed by a body under test. In each radiation, horizontal and vertical polarization components are separated, and then recombined into two different beams comprising radiations at both frequencies, respectively polarized in the same plane. Beatings between the two components of each beam are originated and from the two electrical signals in the radiofrequency range thus obtained the information is extracted on the relative phase and the amplitude of the two components of the radiation with polarization imposed by the body under test.

Abstract: The circuit comprises two registers (SR12, SR8) which temporarily memorize uncompressed and compressed PCM words, respectively. The uncompressed word is sequentially read and a counter (CNT) counts the number of zeroes present in the most significant positions of the absolute value of the word. The compressed word is composed, in the corresponding register, of the sign bit of the uncompressed word, followed by the counting bits of the counter and by the bits of the positions of the uncompressed word following those of the counted zeroes.

Abstract: The system comprises a plurality of units arranged along a unidirectional line whereupon information is transmitted relevant to circuit switched and packet switched communications and organized into hybrid frames comprising a region for each communication type. The units comprise devices handling the access to the line which cooperate with one another and with a frame signal generator, centralized or associated with each unit, to implement in distributed way an ordered protocol without collisions in both frame region, based on physical unit location.

Abstract: A method and an apparatus wherein a light beam is passed through a slit oscillating with respect to the beam, and a periodic signal is obtained from the beam portion traversing the slit. The periodic signal is split into its spectral components. Moment values are derived from the values of the amplitudes of such components.

Abstract: The cut-off wavelength of the first higher order mode in optical fibers for telecommunication is measured based on the fact that the introduction of perturbations in an optical fiber can generate greater losses on higher order modes than on the lower order modes. A spectral scanning of the fiber output power is effected under a certain number of different perturbations conditions and the values obtained are combined so as to determine the fraction of power guided in the fundamental mode. The cut-off wavelength is that where this fraction exceeds a certain value.

Abstract: Voltage reference is generated by a current generator which, through a current-mirror amplifier, biases an enhancement MOS transistor as well as a depletion one, so that the desired voltage is equal to the difference between their threshold voltages.