Abstract: The method of surfacing the heater of a furnace for optical fiber drawing allows elimination of defects in the inner heater surface, which defects give rise to particle emission towards the preform. This is achieved by depositing a thin layer of a mixture of oxides compatible with the material composing the heater.

Abstract: The basic element provided by the invention carries out the basic logic functions of storage and/or transfer of the data applied at the input, typical of a latch. Two ways of embodiment of the basic element having active phase at the high and low level of the clock signal are described. The basic element presents a transfer-gate transistor at the input controlled by the clock signal, followed by an inverter at whose signal leads two positive feedback networks are connected, one of which controlled by the clock signal, to stabilize the logic levels (FIG. 1).

Abstract: The broad-band integrator uses bipolar transistors with single low-value integration capacitor, that is why it is easy to integrate. A bias circuit, which can be integrated, allows both the gain-bandwidth product (G*B) and the absolute values of the currents in the transistors to be programmed by two external resistors. A plurality of integrators, typically sixteen, can be connected to the same bias circuit thanks to their small power consumption.

Abstract: A broadband signal broadcasting system comprising a circuit to encode video and audio signals forming a TV channel to be sent to a switching matrix, which is remotely operated by the subscriber; a circuit to multiplex two or more TV channel to be simultaneously transmitted on the subscriber's line, which can be a coaxial cable, a radio link or an optical fiber; and a circuit to receive the signals transmitted on the line, to separate two or more TV channels and to carry out channel decoding by supplying the subscriber's terminals with the corresponding video and audio signals. The system requires a single encoding and a single decoding of the nB.fwdarw.(n+m)B type on broadband signals, respectively at the output from signal sources and at the input of subscriber's terminals.

Abstract: A method of and an apparatus for measuring the softening point of a vitreous specimen in which the viscosity variation as a temperature function is determined by applying torsion to the specimen and measuring the transmitted torque as a function of temperature.

Abstract: The process for manufacturing halide glasses uses a reaction between organometallic and inter-halide or halide-derived compounds, started at a temperature ranging from the highest melting temperature and the lowest boiling temperature of the compounds used.

Abstract: Speech synthesis is selectable in two modes: "normal" mode in which the synthesis filter is responsive to prestored parameters, and "test" mode which executes a checking procedure based on test words from an outside source. Each mode has corresponding instructions prestored in a memory.

Abstract: The improvements relating to capacitive devices for measuring the diameter of a dielectric fiber are based on a particular shaping of the capacitor plates, such as to allow electric field reductions at the edges to be compensated for and hence capacitance measurements to be unaffected by fibre vibrations.

Abstract: These improvements to semiconductor lasers allow the fabrication of high-efficiency photoemitting devices thanks to a decrease in the threshold current necessary to optical emission stimulation. They consist in the application of a suitable magnetic field apt to confine carrier current within a limited zone of the active layer.

Abstract: This structure for a dichroic antenna can be used in a reflector antenna capable of operating at the same time at two different frequencies or with two orthogonal polarizations, and presents mechanical characteristics allowing its use on board the satellites. The structure, suitable for a subreflector, comprises a plurality of layers with high mechanical stiffness in the external part, followed by layers with low dielectric constant and one or a plurality of metallic grids in the most internal part, separated by low-dielectric constant layers.

Abstract: The local network comprises a plurality of active nodes (N1 . . . Nn) placed along a folded unidirectional bus (1) which presents a writing branch (1W) and a reading branch (1R). The nodes present means (RR) for network reconfiguration in the presence of a failure, through an isolation of the parts concerned by the failure, through an isolation of the parts concerned by the failure, and for regular service restoration after the repair, and means (GA) for the implementation of an ordered access protocol, which is based on the physical position of the nodes (N1 . . . Nn) and allows hybrid frames to be transmitted through the bus (FIG. 1).

Abstract: The monochromator presents, in the plane of the slit (5), a mirror (6) which reflects the radiations comprised within the spectrum portion selected by the slit (5) towards the grating (3) dispersing a non-monochromatic beam. The radiations reflected recombine into a single, substantially monochromatic beam on the grating (3), and a suitable optical system (7,8) focuses such a beam forming the substantially monochromatic image of the source (1).

Abstract: A network for supplying identical biasing voltages and programmable direct currents to a plurality of mutually similar transceivers, connected across respective transmission lines, is integrated with the associated transceivers in a common semiconductor body and comprises a generator of fixed reference voltage determined by the band gap of the semiconductor. The reference voltage is applied in parallel to the bases of several NPN transistors emitting the same biasing voltage as a result thereof. This reference voltage also drives an NPN pilot transistor lying in series with an external resistor through which it draws a small programmed current. Through two cascaded amplification stages formed by NPN transistors operating in the ECL mode, with the second stage designed as a multiple-output current mirror, the programmed current is stepped up to provide the several direct currents required by the associated transceivers.

Abstract: The device consists of a transparent container, partly filled with a ferromagnetic fluid surrounding a bubble of a transparent liquid. By an external magnetic field the ferromagnetic fluid is displaced within the container and moves the bubble making it pass between a light source and a light sensitive element.

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 method uses a raw-material and dopant-deposition technique, which requires vapor-state reactants and thermal sources for producing a temperature gradient suited to obtain a circularly and radially varying refractive-index profile in the supporting tube.

Abstract: Airtight rotating joint, composed of a fixed part and of a rotating one both equipped with an axial conduit ending in a chamber, rendered airtight and separated from the outside by means of a second pressurizable chamber. The joint is particularly suited to equipment where high-purity materials are to be handled.

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.