Abstract: A double interaction switch has a case in which a single block of contactors is controlled by two levers; namely, one monostable lever and one bistable lever. The bistable lever may be locked in one of its two stable positions. When the bistable lever is so locked, the monostable lever may be moved, and actuation of the bistable lever thereafter causes it to return to its unlocked position. When the monostable lever comes back to its rest position, with the bistable lever initially locked, the bistable lever comes back to its rest position. The bistable lever is lockable by means of a rod which may pivot under the action of a labyrinth, provided on the lever. The switch is suitable for use with "hands free" telephone receiver sets.

Abstract: An automatic payment machine is provided for electronically checking the validity of instruments of payment with deliverance of a voucher. It includes means for maintaining the voucher in a waiting position in the path of the instrument of payment so that this latter takes it along with it when it passes, for restoring the instrument and the voucher simultaneously.

Abstract: A digital timer with constant resolution comprising a clock and a chain of binary down-counters, each of which corresponds to a timing range which is a mutiple of that of the preceding down-counter. The binary outputs of the down-counters are fed in parallel to display points of a first set of display points, enabling means being provided so that only the output of the most significant down-counter not at zero actuates the display points. A display point of a second set of display points is associated with each down-counter so that only the display point corresponding to the most significant down-counter not at zero is actuated.

Abstract: A permanent connection public telephone appliance is provided for connection to the switched network by a connection unit. It is permanently fed with power romotely by a source of the connection unit connected in parallel across the line of the appliance. The switched network is isolated from the source by capacitors. Line connection to the appliance is provided by a relay of the connection unit.

Abstract: An oscillator is provided whose oscillation frequency is substantially proportional to the intensity of the ambient magnetic field, and which is used for measuring said magnetic field, and comprising a magnetic resonance magnetrometric probe for detecting a signal at the frequency of said magnetic resonance in response more particularly to a low frequency excitation signal and means for generating said low frequency excitation signal in response to the detected signal, said generation means comprising a loop for locking the phase of said low frequency excitation signal to the phase of said detected signal, and initialization means so that said low frequency excitation signal sweeps a range of frequencies when said loop is not locked.

Abstract: A universal electronic payment terminal base comprising an application and transaction microprocessor (4), with its power supply source (8) and being capable of receiving information identifying memory card holders, and a reader (6) of these cards controlled by the microprocessor (4). The source (8) also serves for programming the cards and delivers a voltage at most equal to the smallest of the programming voltages required. Between the low weight source (8) and the reader (6) a voltage booster (51) is provided for boosting the voltage to a constant level higher than the largest of the programming voltages, and a step by step voltage dropper (53) controlled by a variable cyclic ratio pulse generator (36).

Abstract: The gyrometer comprises a cavity filled with a fluid in the form of a body of revolution having an axis coinciding with the axis of a rotation to be measured. An excitation transducer and a measuring transducer are disposed on the wall of the cavity in a same cross section and offset at an angle of 90.degree.. The excitation transducer excites a first acoustic resonance mode of the cavity and the measuring transducer measures a second mode of resonance induced by Coriolis forces when the cavity is subjected to the rotation to be measured. Such a gyrometer, less sensitive to mechanical embodiment inaccuracies, is assembled on, a moving body, for example, in order to measure its speed(s) of rotation.

Abstract: An electrical interface device for washing and drying machines and the like, has at least one rigid planar element, to which there are firmly applied one or more flexible printed circuits, electrically connected to one another and to the electromechanical and/or electronic programming component of the machine. The edges of the rigid planar element and of the flexible printed circuits are provided with alternating slots and teeth. To the teeth there are applied the terminals of the electrical paths of the circuits, forming in this manner zones adapted for the insertion of electrical connectors of low and high power.

Abstract: A nuclear magnetic resonance magnetometer is provided comprising two semi-coils which pick up precessional signals of the nuclear spins of two samples. A capacitor of a battery of capacitors forms a resonating circuit with the two semi-coils. The signal at the terminals of the capacitor is amplified in a differential amplifier, phase-shifted in a phase-shifter introducing a constant phase-shift of 90.degree., and reinjected into the semi-coils through a potentiometer. The frequency of the oscillations is measured by a frequency meter. A circuit controls the connection of the capacitors of the battery is response to the valve of the frequency measured so as to maintain the parasite phase-shifts between signals picked up and reinjected signals less than a threshold.

Abstract: Frequency measurement involves anti-foldover filtering (1) of an analog signal whose frequency i.e. to be measured, followed by sampling of the filtered analog signal and analog-digital conversion of the samples, then digital band-pass filtering (3) on a slaved basis. Associated calculation (4-7) utilizes a linear regression having a single coefficient a for the linear relation between successive digitized samples (2) and to estimate the coefficient a for approximation of the frequency to be measured. The invention is particularly applicable to signals from a probe having nuclear magnetic resonance used in measuring intensity of the terrestrial magnetic field disturbed by metallic masses.

Abstract: The air speed is determined by solving the equation ##EQU1## in which P.sub.z is the pitch of the antitorque device, .gamma..sub.z, the vertical acceleration of the helicopter, k.sub.1 -k.sub.10, parameters depending on the type of helicopter, p.sub.x,y, the longitudinal or transverse cyclic pitch, p.sub.o the collective pitch of the main rotor, .theta..sub.x,y the angle of bank of the helicopter about the transverse or longitudinal axis of the helicopter. The system for determining the air speed may also include a conventional anemometer for hybridization with the computed speed. The parameters k.sub.1 -k.sub.10 are determined by self-calibration and by assuring that the variations of the ground speed and of the air speed are the same from one flight configuration to another one of a pair of flight configurations, among a series of pairs, for which the sensiting parameters of the helicopter are measured in the earth's reference by means of an airborne ground speed reference.

Abstract: A device is provided for measuring the earth's magnetic field disturbed by anomalies, including a probe in which are mounted, aligned and harmonized with each other, a nuclear magnetic resonance measuring probe associated with its oscillation electronics and the means for compensating for the anomalies due to the carrier: a triaxial magnetometer and a two axis gyrometer. The device can be mounted on land vehicles, ships and aircrafts.

Abstract: A method and device are provided for measuring the propagation time of a wave, wherein a wave is transmitted modulated in amplitude by a modulation signal. The wave reflected by an obstacle is received after a propagation time and the amplitude thereof is detected. The average value of the product of the detected signal and a reference signal is calculated and the delay with respect to the modulation signal is controlled so as to cancel out the average value. The modulation signal and the reference signal comprise a succession of elementary signals chosen so as to allow, in a single measurement, a long propagation time to be determined without ambiguity and with high accuracy.

Abstract: An accelerometer is provided comprising an inertial mass connected to a support by means of a hinge and a vibrating element whose ends are respectively fixed to the inertial mass and to the support. The hinge is disposed in the median plane of the vibrating element and the centers of gravity of the vibrating element and of the inertial mass are merged. The effects of internal thermal stresses, which vitiate the results, are considerably reduced.

Abstract: A device is provided for the temperature measurement and thermal protection of an object and more particularly of an electronic "solid state" circuit, using an analog network representative of a thermal model of the circuit to be protected. It comprises, on the one hand, an initialization device for, at the time of switching on, positioning the state of the thermal model at an operating point representative of the real temperature of the object to be protected and, on the other hand, elements isolating the analog network thus allowing it to be representative of the real thermal state of the circuit to be protected, whatever the state of the circuits internal to said device. The device is appropriate for thermal protection of an electronic power controller.

Abstract: A light panel for the electrical mounting of components of airborne equipment is disclosed and comprises a first rigid plate having a plurality of holes for allowing component operating knobs to pass therethrough, a plurality of rings for individually guiding the knobs as well as holding components associated with the knobs in a fixed position, a printed circuit board having holes corresponding to like holes in the rigid plate and including conducting tracks for supplying electric power to microlamps which illuminate the knobs, and an insulating support plate for supporting component housings and electrically connecting the components to electrical conductors.

Abstract: The invention provides a string resonator vibrating under flexion whose oscillation is maintained by piezoelectric, electrostatic or magnetic exitation means.Decoupling is obtained by inertia masses which oscillate in the vibration plane of the string, between the string and fixing supports, with a movement of rotation about an axis orthogonal to the vibration plane of the string and at the level of flexible elements. The resonator is easy to manufacture, inexpensive and hase a good coefficient of quality. It may be used for force, pressure sensors or gyroscopes.