Abstract: A circuit for encoding and formatting data, the circuit having an input suitable for receiving a data stream in the form of bytes, the circuit comprising firstly a working memory in which the data is stored in the form of a matrix, and from which the data is taken sequentially, with the data being stored and taken by means of respective different sequences (either by being stored in lines and then taken in columns, or else by being stored in columns and then taken in lines), and secondly first and second encoder means each suitable for calculating, respectively for each line and for each column, a given number of redundancy bytes which are respectively horizontal redundancy bytes and vertical redundancy bytes (with one of said encoding means being connected to the outlet of said memory), wherein the first and second encoding means are connected in parallel to the output from the memory, with said second encoding means (for performing redundancy calculations corresponding to the sequence opposite to that by wh

Abstract: In a micromachined silicon pressure sensor comprising a resonantly vibratable beam supported on a diaphragm, the beam is indirectly excited into resonant vibration by directing an optical excitation signal at the beam resonant frequency onto a part of the sensor other than the beam, preferably the diaphragm. Preferably, the optical excitation signal is of a wavelength to which the sensor is fairly transparent, and is directed through the beam and diaphragm to be absorbed by a suitable coating on the underside of the diaphragm. The optical excitation signal produces local heating, and the resulting expansions and contractions at the beam resonant frequency propagate through the sensor structure to excite the beam into resonant vibration. Another optical signal is used to detect the frequency of vibration of the beam, and a positive feedback loop maintains the frequency of the excitation signal equal to the detected beam vibration frequency.

Abstract: A solid state sensor, micromachined in silicon, comprised first and second beams which can be optically excited into resonant vibration. The first beam is arranged to be acted upon by a diaphragm, so that the tension in it, and therefore its resonant frequency, is affected by the pressure applied to the diaphragm. The second beam is provided for temperature correction purposes, and to this end is positioned close to the first beam but free at one end, so that it is insensitive to the pressure applied to the diaphragm, while being subject to the same temperature variations as the first beam. Additionally, the second beam is positioned sufficiently close to the first beam that it can be optically excited simultaneously with the first beam via a single optical fibre.

Abstract: The invention relates in particular to a detector for two-dimensional analysis of a flux of photons or neutral particles. The detector comprises a solid plane converter (5) constituted by a two-dimensional matrix of cells (such as 9c), an array of charge-multiplying wires (6) using stimulated ionization of a gas, and a cathode grid (7). The cells both convert the photons or neutral particles and collect the charge, and the ionization is preferably stimulated until self-regulating streams of electrons appear (streamer mode).The invention has application to imaging devices.

Abstract: An electricity metering interbase device (30) for connecting a primary electrical metering device (40) and a power source (42) includes a generally cylindrical base (32) from which a generally rectangular terminal housing (34) extends, and a cover (36). The cover (36) includes one or more hinge pins (120,122) and the terminal housing (34) includes one or more corresponding hinge slots (80,82) adapted to mate and hingedly attach the terminal housing (34) and cover (36) around an axis of rotation, and allowing removal of the cover (36) from the terminal housing (34) upon disassembly of the hinge pins (120,122) from the hinge slots (80,82) in the direction of the axis of rotation. Barriers (130,132) are provided for preventing disassembly of the cover (36) from the terminal housing (34) when the cover (36) is in a closed position covering the cavity (35) of the terminal housing (34).

Abstract: The pressure sensor is formed of semiconductor material which is formed on insulating support, i.e., as a semiconductor-on-silicon. The sensor is comprised of four piezoresistive gauges formed in the semiconductor material. Two of the gauges, each have a pair of limbs joined by a base, such that they are U-shaped, and two others are I-shaped. Each of the four gauges comprise two half-gauges, and each half-gauge comprises an elongated sensing zone in semiconductor material and having a reduced width in the plane of the insulating support. Two ohmic contact zones are disposed at the ends of each of the half-gauges, and two connection zones in semiconductor material and of greater width are disposed between the sensing zones and the ohmic contact zones, the form of the two connection zones are the same for each of the eight half-gauges.

Abstract: An electromechanical sensor is provided which comprises: first semiconductor wafer including a first stop surface residing in a first shallow recessed region of the first wafer; a second semiconductor wafer; wherein the first and second semiconductor wafers are laminated together such that the first recessed region of the first wafer and the second wafer define a first chamber in which the first stop surface and the second wafer are disposed close enough together such that the first stop surface restrains the second wafer from deflecting beyond the first stop surface; and an apparatus for measuring deflection of the second wafer.

Abstract: An electromechanical sensor is provided which comprises: a first silicon wafer which defines a resonant element; wherein the resonant element is doped with approximately the same impurity concentration as a background dopant concentration of the first wafer; and a second single crystal wafer which defines a device for coupling mechanical stress from the second wafer to the resonant element; wherein the first and second wafers are fusion bonded together.

Abstract: The invention relates to an input circuit for an electrical energy meter, which circuit has a current path and a voltage path, the current path being associated with a mutual conductance transformer. In order to compensate for the differentiating function of the transformer, but without introduicng interference signals, the current path includes an active filter connected as an integrator and provided with a coupling capacitance suitable for blocking low frequency signals.

Abstract: A coriolis-type mass flow sensor suitable for aerospace use comprises a tuning fork which is immersed in the fluid whose mass flow is to be sensed, such that its tines extend across (i.e. perpendicular to) the direction of flow of the fluid. The whole tuning fork is elongated in the direction of flow of the fluid, so that the fluid flows over (and between) the tines: typically, the fork may be up to 15 cm long in the direction of flow. The tines are excited to vibrate perpendicularly to the direction of flow of the fluid by several piezoelectric drive devices held under compression in, and distributed symmetrically about the midlength of, the yoke from which the tines project, while the vibrations are sensed by respective piezoelectric pickup devices within each end of the yoke. The phase difference between the vibrations sensed by the two pickup devices is a function of the mass flow of the fluid.

Abstract: A gas flow correction sensor for producing an output signal proportional to the ratio between line pressure and line temperature for gas flowing in a line, for use in correcting the output of a volumetric flow meter connected in the line, comprises a sealed chamber containing a fixed mass of a reference gas. The sealed chamber includes a bellows portion subjected to line pressure, thus maintaining the reference gas at line pressure. Additionally, the sealed chamber is thermally insulated and includes at least a portion disposed in a thermowell immersed in the line, so as to maintain the reference gas at line temperature. A vibrating quartz density sensor is also mounted in the thermowell, so as to produce an output signal whose frequency is proportional to the density of the reference gas, which can be shown also to be proportional to the desired line pressure to line temperature ratio.

Abstract: An ultrasonic distributed temperature sensor comprises an elongate ultrasonic waveguide in the form of steel or nickel wire 0.16 cm in diameter and up to 10 meters long, which is strung around the area whose temperature is to be monitored, eg an aircraft engine. The wire is provided with discontinuities in the form of annuli welded on to it to form annular flanges, which serve to partially reflect ultrasonic pules launched into one end of the wire. These flanges, known as "posi-notches", divide the waveguide, and thus the area to be monitored, into a number of zones, the size of each zone being determined by the spacing of the adjacent flanges defining it. In operation, the temporal spacing of each pair of successive partially reflected pulses is a measure of the average temperature of the zone defined by the flanges producing that pair of pulses.

Abstract: A coriolis-type mass flow transducer comprises a straight tube 10 through which a fluid whose mass flow rate is to be measured is arranged to flow while the tube is set into transverse resonant vibration in its second overtone mode. Mass flow is determined by measuring the phase difference between the vibration at two points along the tube 10. Such a transducer exhibits an offset at zero flow, which can vary with time. These variations are minimized by minimizing the damping effects on the tube 10 of bellows 6, 7 used to connect tube 10 in a flow line, and then corrected by measuring the amplitude ratio of the vibrations at the two points, and correcting the initially-determined offset in dependence upon changes in this amplitude ratio.

Abstract: A device for driving magnetic tape suitable for running from a pay-out spool to a take-up spool along a determined path during which the tape is wound through a given angle around a stationary element such as a cylindrical drum provided with rotary heads, and is caused to slip over the surface thereof, the device comprising first and second drive elements disposed respectively upstream and downstream from the element, wherein one of the drive elements includes a capstan and wherein the other one of the drive elements includes a wheel having the tape wound thereabout, the wheel being rotated so that its linear speed is greater than the linear speed of the tape and is in the same direction as the linear speed of the tape, and is suitable for enabling the tape to slip over the wheel.

Abstract: The invention relates to a neutral particle detector for providing one-dimensional analysis of a flux (14) of neutral particles which reach it in a sheet. The detector comprises a solid plane converter (17) disposed at a grazing incidence, a grid of charge amplifying wires (18) making use of stimulated ionization of a gas, and charge collecting tracks (19). The tracks are disposed in the immediate proximity of the converter and are subjected to the same electrical potential as the converter. The invention is applicable to imaging.

Abstract: Optimum routing for communications between a central control unit (CCU) and remote units (nodes), such as electricity meters, distributed on an electrical power line is established by broadcasting from the CCU an interrogation signal to be received by the remote units. In response to a receipt of the interrogation signal, each remote unit returns an acknowledgement signal, time multiplexed with the acknowledgement signals of the other remote units, to the CCU which determines which units, if any, are "mute", i.e., have not acknowledged. The CCU then selects remote units in proximity to the mute remote units if it has already a good knowledge of the network or at random otherwise, to function as relays and repeats interrogation of the remote units via the relays. This process is repeated, if necessary, until communication paths between the CCU and all remote units are established directly or via delay units, to form maps.

Abstract: A differential electrical current shunt which is particularly adapted for the measurement of large currents with high accuracy and substantially free of errors due to ageing, connection resistance and differentials therein and thermally induced resistance changes. The shunt, according to the invention divides the large current into two substantially equal portions by forming a preferably elongated aperture in a conductor carrying the large current; the two portions of the conductor formed by the aperture having substantially equal but slightly differing resistances. The two conductor portions are formed with respect to a core such that the conductor portions each form a single turn coil on the core with the induced flux from each conductor portion opposing that included in the coil by the other of the two conductor portions.

Abstract: A liquid bottle is efficiently carried by a bicycle having a tubular frame that includes a forwardly extending first tube projecting forwardly from near the seat to the steering column, and a second tube projecting downwardly and rearwardly from the steering column at an angle .alpha. relative to the first tube and toward the pedal rotor bearing, the two tubes defining an upright frame plane that extends forwardly.

Abstract: Amplitude-balanced input signals (I.sub.1 and I.sub.2) from two pick-up coils spaced along a vibrating tube mass flow transducer are used to form sum and difference signals (S and D). These are multiplied by quadrature and in-phase signals (Q and I) respectively in multipliers, the multiplying signals being generated by a phase-locked loop locked to the sum signal (S). The in-phase signal (I) provides the drive signal for a drive coil (12) of the transducer. The product signals (P.sub.S and P.sub.D) from the two multiplier are smoothed in low pass filters to provide sum and difference voltages (V.sub.S and V.sub.D). Mass flow rate is proportional to the phase difference (represented by the ratio of these voltages) divided by the frequency of the I signal. The density of the fluid in the transducer is indicated by the frequency of the I signal.

Abstract: An ultrasonic fire detector comprises an elongate ultrasonic waveguide, e.g. in the form of a wire, which is arranged to be strung around the area to be monitored for fire. An ultrasonic pulse generator launches longitudinal ultrasonic pulses into one end of the waveguide, for reflection from the far end. The waveguide is arranged such that local heating due to a fire changes its acoustic impedance at the location of the local heating, the change in acoustic impedance being sufficient to produce partial reflection of the ultrasonic pulses. Detection of the partially reflected pulses thus indicates the presence of a fire, and their time of arrival gives the location of the fire along the waveguide. The acoustic impedance change can be produced by providing the waveguide with notches filled with low melting-point alloy, by applying a temperature-induced stress to the waveguide, or simply by the temperature gradient caused by the fire.