Abstract: The method relates to the detection of the training sequence of a self-adapting equalizer at the receiver end of a synchronous data-transmission system, the training sequence being preceded a synchronizing transmission of data transformed on coding into a succession of multivalent symbols such that the transmitted signal has a frequency spectrum which is substantially a single large-amplitude spectrum line. The training sequence begins with the transmission of data transformed on coding and at least one null symbol. The method consists in detecting the presence of the large-amplitude spectrum line in the signal formed by the received but not yet equalized symbols by means of a digital filter 40 and in thereafter detecting the first following major drop in absolute amplitude of the signal that lasts throughout the duration of one symbol period. This is done by means of a low amplitude level detector 50.

Abstract: An addressing circuit has a register search counter (20) connected to a first multiplexer (24) and to a second multiplexer (25), a memory (33) connected to the output of the first multiplexer for writing the type of processing of each register, a register counter (26) connected to the second multiplexer which is itself connected by its output to three address registers (28, 30, 32) in series. The output of the second register (30) is connected to the first multiplexer to write address the memory under the control of a write signal (CRW). The register search counter read addresses the memory and stops as soon as a register requiring rapid processing is detected; the second multiplexer receives a transfer signal (ST) to transmit the address applied to the output of the register search counter; the register counter (26) stops during the transfer signal.

Abstract: A multiple stylus print head, e.g. for printing a document in a facsimile system, has at least two parallel lines of styluses with the styluses being offset from one line to the next. Each line of styluses is built up from several tiers of interdigitated conductor pins (C) having tips that constitute the styluses per se. The tiers of pins are held together by respective strips of insulating material (7) forming comb-like structures which are then stacked together in such a manner that the combs fan out from the line of styluses. A plurality of groups (G.sub.1, G.sub.2) of stylus line forming comb structures are stacked together into a single stack.

Abstract: In a method of detecting the presence of speech in a telephone signal, a signal sequence is interpreted as constituting speech if its mean power level exceeds a threshold, the value of which is decreased as the number of passages through zero level in the sequence approaches 1.25 per millisecond (0.25 Hz). A speech detector implementing this method receives pulse code modulated signal samples on its input. It comprises a squaring circuit driving a digital accumulator whose output signal is proportional to the mean power level of each of consecutive 4 millisecond signal sequences. A change of sign detector and a second digital accumulator indicate the number of passages through zero level in each of these sequences. Banks of threshold comparators and a selector circuit are used to choose between the various threshold values. The selected value is lowest when the number of passages through zero level is between 5 and 6 per millisecond.

Abstract: The power supply system comprises three levels: a primary level (PRI), a secondary level (SEC), and a tertiary level (TER). The secondary level is constituted by power supply circuits (S1 to Sn) which provide galvanic isolation between the primary and the tertiary levels, and which provide at least one intermediate voltage at a fixed level relative to a system reference potential (point R). The tertiary level comprises chopper power supplies (RD), converters (CV), and inverters (OND) connected to user equipment (UT).

Abstract: The pump comprises a pump stator (5), an electric motor stator (4), and a rotor (6) that constitutes the rotor both of the pump and of the electric motor. The pump stator comprises a tubular non-magnetic lining to the electric motor stator, and the rotor is mounted excentrically inside said tubular lining and is equipped with radially movable vanes (63) that co-operate with said lining to provide pumping action when the rotor rotates. The arrangement is particularly applicable to oil-sealed vacuum pumps, and has the advantage of being more compact than units of similar performance, but equipped with a pump and a motor that are separate and interconnected by a mechanical coupling, as is conventional practice.

Abstract: A method and apparatus for accentuating the features of a monochrome image reproduced by means of a digital transcription.The apparatus includes an analog portion disposed between the digital-to-analog converter DAC (5) and an analog-to-digital converter (15) with analog sampling units (6,7), comparators (10,11,12), a subtractor (9) an amplifier (13) and a limiter to select and calculate the corrective term depending on the difference and on the digital processing means (17,18,19 and 20) to add the corrective terms to the numbers of the digital transcription.

Abstract: An apparatus for constituting a rotary magnetic brush comprises a hollow cylindrical member (11) with permanent magnetic strips arranged axially along its periphery. The strips have outwardly directed magnetic poles in a configuration in which north poles and south poles alternate circumferentially. A tube (13) made of non-magnetic substance surrounds said member without touching it. The tube is intended to have particles of magnetic powder deposited on its surface and the particles are made to rotate by rotating the member (4). This causes a rotating layer or "brush" of magnetic particles to be formed on said tube. Said member (11) and the tube (13) which surrounds it are longer than the "brush": An end portion projects beyond the "brush" and is housed in an electrical stator (14) which drives the member (11) by making use of the poles which form the brush. The invention applies to developing electrostatic latent images.

Abstract: The invention relates to a high-speed hard vacuum rotary pump. A hard vacuum rotary pump which includes a rotor (2) driven by a motor (20) disposed on the outside of the pump body and connected to the motor by a drive shaft (1) which is sealed by a grooved dynamic seal (8) is characterized in that said shaft is supported firstly by an outer bearing (6) disposed on the outside of the pump body (4) and secondly by an inner bearing (5) disposed inside the pump body and lubricated with grease. The invention applies in particular to molecular and turbomolecular vacuum pumps.

Abstract: Disclosed is a phase-locked loop which comprises a voltage controlled variable frequency oscillator (1), a phase comparator (2) having a cosine characteristic and receiving a reference oscillation as well as that supplied by the oscillator (1), and a low-pass filter (3) connected between the output of the phase comparator (2) and a frequency control input of the oscillator (1).The transfer function of the low-pass filter (3) is switchable between two characteristics depending on the instantaneous phase difference between the reference oscillation and that supplied by the oscillator. The first low-pass filter transfer function is adapted to the phase-locked operation of the loop, while the second transfer function is adapted for frequency capture.

Abstract: This invention relates to a method of encoding data by transitions in a binary sequence, as well as to a coder and a decoder using the method. In the method data is encoded as follows: a first value bit is encoded by a transition in the middle of the corresponding bit-time, but this transition is inhibited if there was a transition in the middle of the previous bit-time, a second value bit is encoded by a transition at the beginning of the corresponding bit-time, but this transition is shifted from the beginning to the middle of the bit-time if there was a transition in the middle of the previous bit-time.

Abstract: A series connection of n diplexers is used as a multiplexer for separating a hyperfrequency band into n + 1 sub-bands (or vice-versa). Each diplexer comprises a semi-circular inlet coupler followed by a semi-circular high-pass filter and by a semi-circular outlet coupler, the filter at each stage is dimensioned to reflect only the lowest of the sub-bands which it receives from the previous stage. The creation of unwanted parasitic modes in the reflected sub-band is avoided by so choosing the radius of the inlet coupler that the reflected sub-band lies between the frequencies at which the parasitic TE.sub.12 and TE.sub.22 modes occur. This is achieved by use of the relationship ##EQU1## WHERE V IS THE SPEED OF LIGHT, FMAX AND FMIN ARE THE UPPER AND LOWER LIMIT FREQUENCIES OF THE REFLECTED SUB-BAND AND P'.sub.12 and P'.sub.22 are the second zeros of the first and second order Bessel functions characterising the respective semi-circular TE.sub.12 and TE.sub.22 modes.

Abstract: The invention relates to the frame synchronization of a first binary pulse train with a second binary pulse train. According to the invention, three looped shift registers are provided which each have a capacity of one complete frame and two identical control circuits are provided which cyclically respectively connect the input and output of the device to the inputs and outputs of the registers. In the case of divergence of frequencies between the two pulse trains, one complete frame is either repeated twice or completely omitted.

Abstract: A device for decoding a Miller-encoded message in the form of binary data at a clock frequency F. The decoder comprises: a transition detector which provides a very short pulse at each transition in the encoded message; first means controlled by a local clock at frequency F to pass only those short pulses which have the same phase; second means for stretching the short pulses passed by the first means to a duration of (1/2F); a local clock phase lock loop acting on a voltage-controlled oscillator of the local clock and responsive to the output signal of the second means; and a flip-flop to sample the output of the second means under the control of the local clock.

Abstract: The invention relates to a connector for optical fibres. The connector between two fibres comprises a pressing assembly formed by three rolls inside a flexible casing and two cones partly engaged inside the pressing assembly, at its respective ends, and a means for actuating one of the cones in a linear movement to control the opening and closing of the pressing assembly on the ends of the fibres. The invention applies to the transmitting of data by a light beam.

Abstract: The invention concerns a position measuring device used for measuring the position of a vessel equipped with three hydrophones arranged at the apexes of a triangle in relation to a transmitting beacon on the sea bed. Measuring of the differences in the travel time between the beacon and the various hydrophones as well as of the depth of the water and analogic calculating of the position of the vessel in a simple way and without approximation. Application to offshore drilling vessels.