Abstract: For controlling the attitude of the body of an earth satellite placed on a low orbit, values of components of the geomagnetic field of the earth are measured along three axes of a frame of reference bound to the body. The values are derivated with respect to time, and multiplied by a gain. Currents responsive to the multiplicated derivatives are passed through magnetic torquers located along the three axes of the body to create magnetic torques that bias the body to a fixed angular position relative to the field lines of the geomagnetic field. Such steps are continuously carried out during eclipse periods. Out of eclipse periods, the pitch of the body is controlled by modifying an internal momentum in response to a signal provided by a solar sensor, so as to maintain solar generators carried by the body of the satellite oriented towards the Sun.

Abstract: A slatted base for a bed having elastically deformable supporting slats which connect longitudinal supports with mutually spaced spring slats running transverse to the longitudinal supports. The spring slats collectively form a supporting surface for a mattress. The middle area of the supporting slat is more elastically deformable than the end areas to provide more sleeping comfort.

Abstract: The volume of space, in range, azimuth and elevation, over which a conventional Tactical Ballistic Missile (TBM) early warning radar is required to search for incoming missiles is very large. This placed very heavy demands on the radar designer, resulting in large, very high power, low mobility radars, with subsequent vulnerability to ARMs and other defence suppression systems. This invention proposes an alternative approach to a TBM early earning radar which considerably reduces both the design and vulnerability problem, and permits effective TBM early warning radars to be constructed using current technology. This is achieved by moving the radar (1) beyond the front edge of the defended area (2). The increased elevation scan requirements are more than compensated for by a range-adaptive scanning technique which reduces the volume search time by more than 50% compared with a more conventional arrangement.

Abstract: This analog-digital conversion device comprises switching means (CS) having two close and centered triggering thresholds; a NOR logic gate (PL) which, when the conversion device is not being used, receives a standby command signal and delivers a zero digital output signal (NOUT) imposed on the input (NIN) of the switching means (CS); preamplification means (PS); and amplification means (AS) receiving a standby command signal and delivering either the digital output signal (NOUT), in the absence of a standby command, or a zero-value signal in the event of a standby command.

Abstract: In order to process an input signal exhibiting a frequency modulation about an intermediate frequency, the demodulator includes a first mixer for producing a first signal exhibiting the frequency modulation about a transposition frequency lower than the intermediate frequency; a switched-capacitor phase-shifter receiving the first signal so as to produce a second signal exhibiting, with respect to the first signal, a phase-shift varying substantially linearly with frequency about the transposition frequency; two substantially identical low-pass filters receiving the second signal and the first signal respectively; and a second mixer for mixing the signals produced by the first and second low-pass filters, in order to deliver a baseband output signal.

Abstract: A three-state output interfacing device for a CMOS memory that comprises a stage for selective control of the device, receiving an input signal (I) at the bit frequency and a control signal (e) and making it possible to deliver, on two ports (A) and (B), either complemented signals (I), or distinct logic levels for driving the device into the high-impedance state, a first inverter stage delivering first inverted logic signals, from the ports (A) and (B), on two ports (C) and (D), a second inverter stage delivering second inverted signals from the ports (C) and (D), a stage for reducing the analog difference between the second inverted signals and for switching the output interfacing device into high-impedance state at ports (E) and (F), and an output stage receiving the signals from the ports (E) and (F) after reduction of analog difference and making it possible to fix and balance the current for charging and discharging the output capacitance of the output interfacing device and its high-impedance switching

Abstract: This invention relates to a shock absorber for use with a command link controlled missile system. The shock absorber being designed to absorb the shocks produced by launch and missile movements and being particularly applicable to fibre optic command link systems.

Abstract: In accordance with the present invention, a system and method for converting an implementation of a logic description describing a field programmable device into an implementation of the same logic in a factory-programmed device are provided. In one embodiment of the present invention, an expert system synthesizes a logic circuit model based on the logic description. An automatic test pattern generator provides test vectors including expected response signals for the logic circuit model generated by the expert system. The automatically generated test vectors are provided to a tester which applies the test vectors as input stimuli to the field programmable device. The output signals of the field programmable device are verified against the expected response signals.

Abstract: In the recognition phase, the signal originating from a sensor is processed to obtain parameters which are compared with those stored in a dictionary in the learning phases so as to recognize the voice structures uttered by the user in a noisy environment. The obtaining of the said parameters during the learning and recognition phases includes the formation of digital frames of predetermined length from the signal originating from the sensor, the transformation of each frame from the time domain to the frequency domain to obtain a spectrum X(i), and the application of an inverse transformation, from the frequency domain to the time domain, to the magnitude .vertline.X(i).vertline..sup..gamma., where .vertline.X(i).vertline. represents the modulus of the spectrum and .gamma. represents an appropriate exponent.

Abstract: An ion thruster comprises a chamber in which propellant is ionized and an accelerator grid, whereby a flow of ions out of the chamber provides reactive thrust. Charge exchange between neutral atoms of propellant and fast moving ions produces slow ions which impact on the accelerator grid and erode it by sputtering, thus limiting the lifetime of the thruster. The invention includes an accelerator grid comprising a layer which includes graphite providing resistance to erosion and a support layer which overcomes the restrictions on engineering and strength of graphite. The accelerator grid can be constructed by machining a block of graphite 12 to produce an upper surface 13, to which the molybdenum grid 14 can be fixed. The block 12 can then be cut away to permit the graphite to be machined to the same contour as the surface 13. Apertures are drilled through the graphite using the existing apertures of the grid 14 as guides.

Abstract: A method of fabricating a read only memory consisting of a matrix of arrays of enhancement-mode or depletion-mode programmed MOS transistors that consists, on a silicon substrate (SU) of a first conduction type, in defining by masking, retrograde wells of the same conduction type as that of the substrate, and then retrograde wells of conduction type opposite to that of the substrate. Removal of the protective oxide allows thus to predefine the enhancement-mode and depletion-mode transistors.

Abstract: A clock recovery circuit comprises first and second voltage-controlled oscillators having identical characteristics. The first oscillator is incorporated into a frequency synthesis loop in such a way as to oscillate, in response to a first control voltage, at a frequency equal to a reference frequency multiplied by a number N. The second voltage-controlled oscillator is incorporated into a phase tracking loop which, when activated, locks its oscillation phase relative to that of the received data signal. The second oscillator delivers the recovered clock signal. A comparator determines whether the frequency of the second oscillator, divided by N, satisfies the condition of not deviating from the reference frequency by more than a predetermined limit value. The phase tracking loop is activated only when the latter condition is satisfied, and the first control voltage is fed to the control input of the second oscillator when the condition is not satisfied.

Abstract: The telescope includes at least one primary concave mirror (MI) for receiving an incoming image and relay optics for enlarging the image reflected by the primary mirror. The relay optics comprise a secondary mirror (M2) and a tertiary mirror (M3), each having a central aperture (12, 13) and each being positioned coaxially with the primary mirror (M1). The secondary mirror (M2) receives the image reflected by the primary mirror (M1) through the central aperture (13) of the tertiary mirror (M3). The tertiary mirror (M3), positioned close to the focal plane of the primary mirror (M1), receives the image reflected by the secondary mirror (M2) and reflects that image through the central aperture of the secondary mirror (M2).

Abstract: The input acoustic signal is subjected to high-pass filtering. The energy of the high-pass filtered signal is compared with that of the unfiltered signal in order to determine a state of the signal from among a first state for which the energy of the high-pass filtered signal is above a predetermined fraction of the energy of the unfiltered signal and a second state for which the energy of the high-pass filtered signal is below the predetermined fraction of the energy of the unfiltered signal. The high-pass filtered signal subjected to pre-emphasis of the high frequencies is addressed to the input of the coder when the signal is in its second state.

Abstract: A speech signal digitized as successive frames is subjected to analysis-by-synthesis in order to obtain, for each frame, quantization values of synthesis parameters allowing reconstruction of an estimate of the speech signal. The analysis-by-synthesis includes short-term linear prediction of the speech signal in order to determine the quantization values of the coefficients of a short-term synthesis filter. A spectral state of the speech signal is determined from among first and second states such that the signal contains proportionally less energy at the low frequencies in the first state than in the second state, and one or the other of two modes of quantization is applied to obtain the quantization values of the coefficients of the short-term synthesis filter depending on the determined spectral state of the speech signal.

Abstract: For demodulating a phase-modulated signal having 2M states of a carrier (M being an integer), the signal is converted into two baseband signals in quadrature. For that, they are multiplied by a signal delivered by a local oscillator at a transposed carrier frequency. Then the baseband signals are digitized by sampling at the clock frequency of the modulating signal. The clock of the signal is recovered by adjusting the phase of a local clock, stabilized at a bit frequency. For that, a minimum value of the intersymbol interference is searched. The signal clock is recovered before the carrier is recovered. Devices for implementing the method are also disclosed.

Abstract: For active damping of vibration at a location subjected to a primary vibration field, a vibratory wave is generated by adaptive filtering of a reference signal and interferes with the primary field at the location. The residual amplitude of vibration at the location is measured, and filtering is adapted automatically to cancel the residual amplitude as measured. The reference signal is divided into a plurality of individual reference signals that are sine-shaped each containing only one of the plurality of frequencies at which the primary field presents a significant energy, with each individual signal being subjected to a respective adaptive digital filter, and the vibratory wave is generated from the sum of the individual filtered signals. An apparatus for implementing the method comprises n processing paths or channels, each having an actuator driving a digital filter, fed with a sine-shaped signal at a frequency corresponding to a concentration of vibratory energy to be damped.

Abstract: A three axis stabilized geostationary satellite comprises a structure having walls that face North and South when the satellite is on station and carrying at a storage battery of large capacity. The storage battery is constituted by cells mounted on a chassis having a base plate oriented North-South and mechanically secured to sides that face North and South when the satellite is on station. The sides carry thermal radiators that are thermally connected to each other and to the cells. Typically sides are in alignment with North and South faces of the structure and extend away from the Earth.

Abstract: A camera device comprises a first detector having opto-electronic sensors for enabling an entire image to be input simultaneously, and associated with an optical system of long focal length. A second detector is associated with an optical system that gives a large field of view, covering the field of the first detector and extending beyond it. The camera device also includes means for synchronizing the images taken by the two detectors and for recording them.

Abstract: The chip is fixed to a substrate by its lower face. At least one wire-bonding adaptor in the form of a board is used, the upper face of which has first bonding pads along at least one first edge and second bonding pads along at least one second edge, and including electrical connections between the first and second bonding pads. The wire-bonding adaptor is adhesively bonded by its lower face to the upper face of the chip so that the said first edge is adjacent to a row of output pads located elsewhere than on the periphery of the upper face of the chip and so that the said second edge is adjacent to the periphery of the chip. Bonding wires are bonded, on the one hand, between the output pads of the said row and the first bonding pads and, on the other hand, between the second bonding pads and conducting pads on the substrate.