Abstract: A probe for fault-actuation devices has a transistor which is utilized to insert a reference signal into a fault-insertion point. The emitter and collector are connectable to the fault-insertion point and a reference signal and a capacitor with a capacitance greater than the capacitance of parasitic components is connected between the base and the emitter.

Abstract: A method and an apparatus are provided for introducing reference impairments into pictures to be used in subjective tests on digital video signals, in compliance with ITU-T Recommendation P.930. The method generates blockiness distortion and/or edge busyness distortion. For the first distortion, areas close to picture edges are selected and, through a movement characteristics analysis, blocks are identified that belong to said areas and that are concerned only by the actual movement of the subject and, for blocks chosen among the identified ones, the luminance value is replaced by a value linked to the individual pixel luminance and to the average block luminance value. For the second distortion, echoes are applied that are randomly chosen in a prearranged set and that alternate at random.

Abstract: A phase locked loop circuit includes an input comparator (2) capable of generating a deviation signal which can be used for driving an oscillator (5) so as to generate an output signal (CLKOUT) locked to the input signal. The oscillator (5) can operate according to a plurality of characteristics under the control of a control circuit (8) including searching circuits arranged to carry out a first search phase by scanning the family of characteristics admitted for the operation of the oscillator (5) by bands of progressively reduced width, according to a general, dichotomic procedure. Upon completion of this first search phase, additional circuits of fine search are destined to identify the optimum operating point, compensating possible fluctuations of the characteristics.

Abstract: The delay element consists of a differential amplifier (M15, M8, M2, M6, M5) in which the load transistors (M2, M5) are associated to respective gate biasing transistors (M21, M22) connected in a source follower configuration, and to feedback transistors (M3, M4), which implement a negative impedance in parallel to a positive impedance represented by each of the load transistors (M2, M5). The modulation of the delay is achieved by modulating the bias currents of the load transistors (M2, M5), the feedback transistors (M3. M4) and the gate biasing transistors (M21, M22).

Abstract: The present invention aims to provide apparatus to measure the beat length, the correlation length, the polarization mode dispersion and other characteristics of single mode optical fibers related to the two polarization modes of the fiber at different positions along the length of the fiber. The present invention also aims to provide apparatus for the measurement of characteristics of an optical fiber with access to only one end of the fiber.

Abstract: A device (DC) is provided for compensating process and operating parameters variations in a CMOS integrated circuit. The device comprises means (CP, CT) for generating a first and a second compensation signals which depend on quality indexes of the fabrication process of the P and N transistors of the integrated circuit and on the operating temperature, and which are capable of compensating deviations of the controlled quantity from the desired value, due to the deviation of the quality indexes and temperature, respectively, from a typical value which would originate the desired value for the output parameter. The compensating device also can be implemented in the form of CMOS integrated circuit, preferably jointly with the device (OS) to be subjected to compensation (FIG. 1).

Abstract: An electronic telecommunications module has circuit components and conductors forming a telecommunications circuit having insertion points at which signals can be applied for test purposes and monitoring points from which responses can be tapped. The insertion and monitoring probes are mounted on the module and are connected to the respective points by shielded microcoaxial cables and the probes are connected by shield and microcoaxial cables on the connectors to allow interfacing between the particular module and the testing and diagnostic system.

Abstract: A method and a device for recognition of isolated words in large vocabularies are described, wherein recognition is performed through two sequential steps using neural networks and Markov models techniques, respectively, and the results of both techniques are adequately combined so as to improve recognition accuracy. The devices performing the combination also provide an evaluation of recognition reliability.

Abstract: A current reference generator comprises a pair of identical units (G1, G2) which generate respective current references (I1, I2), and a circuit (CL) for the linear combination of the two references. In each of the two units, the elements (S1, S2) which, by their current-voltage characteristics, determine the working point comprise respectively a single transistor (T1) and a pair of transistors (T2, T3), of the same type as the first, connected in series. A differential amplifier (AD) maintains stable the working point of the respective unit as power supply voltage varies. (FIG.

Abstract: A phase locked loop (1) including an oscillator (5), usually made as a voltage controlled oscillator (VCO), arranged to operate selectively according to different input/output characteristics. The circuit further includes a control circuit (81) for selectively controlling the operation of the oscillator (5) thereby making the oscillator (5) itself operate on one of an optimum characteristic selectively determined according to the operating conditions of the loop (1).

Abstract: The circuit for motion estimation in digitised video sequence encoders comprises at least an integrated circuit component (IM, IM1 . . . IMn) which is arranged to perform either the function of determining motion vectors and associated costs for different prediction modes, or the function of vector refinement, possibly in addition to prediction mode selection. The circuit (IM) is based on the use of two operating units (M1, M2) which are arranged to concurrently process in different ways different pixel groups according to a MIMD technique. Preferably, when the circuit performs motion vector determination, the operating units (M1, M2) are programmed to execute a genetic algorithm exploiting an initial vector population taking into account the temporal and spatial correlations in the picture.

Abstract: Audio sources are coded by recognizing different classes of audio such as speech and music. The classes are used to select between coding algorithms and to provide object definitions. Objects have abstract and concrete classes which may further rely on parameters produced by linear prediction and subband filters to provide a frame-based bit stream of information. Each object in the bit stream has layers of information such as basic bit rate, coding parameters and enhancement parameters. The layers of information in each object allow altering selected parameters to manipulate audio signals.

Abstract: A device and a method for aligning in time two essentially isochronous digital signals are provided, in which a plurality (2.sup.n) of replicas (CK1-CK4) of the first signal (CKIN), separated by a given phase difference, are generated and a number of said replicas (CK3, CK4) is subjected to sampling (4, 5) in correspondence with the rising edges of the second signal (DATA). As the result of the sampling, a combination of logic signals (SL0, SL1) is obtained which is representative of the phase relation existing between each of said replicas (CK1-CK4) and the second signal (DATA). The output signal (CKOUT) of the device, aligned with the second signal, corresponds to the one, among the replicas (CK1-CK4) of the first signal, which best reproduces the desired alignment condition.

Abstract: In an induction furnace for the synthesis of glasses, in particular fluorozirconate glasses for optical fibres for telecommunications, the support device (6') for the crucible (3) is associated with a pair of sleeves (7, 9) between which an annular element (8) which constitutes the actual support element is inserted. The first sleeve (7) has such longitudinal dimensions that the crucible (3) is supported in the annular element (8) in such a way as to be spaced from the planar element (5'), and the second sleeve has such longitudinal dimensions that its top edge is at a level higher than that of the top edge of the crucible (3), to obtain a homogeneous temperature region extending at least along the entire height of the crucible (3).

Abstract: An active single-mode optical fiber has the core made of a rare earth doped non-oxide glass and the cladding made of an oxide glass. The glass of the core has a melting temperature lower than that of the glass of the cladding and lying within the range of the softening temperatures of the latter. In a preferred embodiment the core is made of a chalcogenide glass and the cladding is made of a lead silicate glass. To produce the fiber, a preform, obtained by introducing an element made of the non-oxide glass into the hole of a capillary tube made of the oxide glass, is brought to a temperature lying within the range of softening temperatures of the oxide glass and not lower than the melting temperature of the non-oxide glass, and is drawn. The capillary tube, during the drawing process, serves as a container for the molten glass of the core.

Abstract: A method and a device are described for the simultaneous fabrication of identical Bragg gratings in different optical fibres or optical waveguides. The fibres/waveguides (1) are mounted side-by-side on a common support (2), along with a phase mask (3), which gives the desired intensity distribution to a writing radiation of the grating. Said common support (2) is reciprocated transversally to the longitudinal axis of the fibres or waveguides, at an appropriately low frequency such that each fibre/waveguide is exposed to such a radiation, at each pass under the radiation, for a time sufficient to start a refractive index change.

Abstract: The signal to be controlled is sent along an optical fiber by a wavelength tunable laser whose emission wavelength may be varied as a function of a possible phase variation in the received signal with respect to a reference phase. At the receiving end of the fiber a control signal is generated by extracting a fraction of the power associated with the received signal and sending such fraction back towards the transmitting end, and at the transmitting end the phase of the fraction is compared with that of the original signal and the tunable laser is driven in such a way as to transmit a wavelength such that the clock information reaches the receiving end with the reference phase.

Abstract: An integrated circuit for manipulating digitized video sequences is provided, for use in a system for transmission and reception of compressed video sequences to perform, possibly with the aid of an external memory, reordering, format conversion, prediction and motion compensation on the pictures in a sequence. The device has memory for temporarily storing sequences to be manipulated and data read from the external memory; a circuit for decoding information about the manipulations to be performed; address circuitry for transferring the data between the device and the external memory; circuitry for configuring the device by means of a remote processing unit; circuitry for processing the data read from the external memory; and circuitry for arranging the output sequences in the format required by the function to be performed. A controller may control, supervise and set up the functions to be performed.

Abstract: A multi-mode, typically triple-mode, cavity (1), for waveguide band-pass filters is disclosed, which cavity requires no tuning or coupling screws and rounded. The cavity comprises a waveguide element such as an iris (IR1) or a waveguide segment (CR2) arranged in a generically eccentric position with respect to the general development of the cavity and in particular to the main axis (Z) of the same. The cavity may be used to make narrowband filters for satellite communications. A filter comprising cavities (1) of the type described can be designed entirely using an electronic computer and requires no calibration procedure.

Abstract: The optical add/drop multiplexer has a pair of nominally identical interference filters, one of which carries out the function of extracting a carrier from a wavelength division multiplexed stream and the other the insertion function. The filters are arranged in parallel planes and are secured to opposite faces of a transparent plate so that the stream exits the device after having undergone reflection by both filters. The plate is mounted on a support which can be rotated in either direction to vary the tuning wavelength of the filters.