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 present invention relates to 1+1 type carrier telephone transmission systems for connecting two subscriber terminals to a telephone exchange via a common two-wire link, one of the terminals being connected via the conventional audio channel, and the other terminal being connected by a channel referred to as a super-audio channel. Disturbances caused in the super-audio channel by signalling, dialling and calling signals of the audio channel are reduced by inserting a current-limiting two-port network in series in the audio channel and at the exchange end of the 1+1 system, in between the filter which separates out the audio channel and the rest of the exchange. Advantageously, an interference limiting low-pass filter (50) is also placed in series on the audio circuit. It has a capacitive shunt arm with a mid point connected to exchange battery ground.

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: Image printing stylus bar, manufacturing method therefor and image printing device.The present invention relates to an image printing stylus bar with as many styli as there are image points on a scanned line on a document to be reproduced, a manufacturing method therefor and a printing device constituting an application thereof.The stylus comprises 2.m register stage chips (59, 60) each having a serial data input, n parallel outputs, a serial data output and control inputs, disposed on at least one film (57, 58) and connected in series in groups of m to constitute two shift registers, the parallel output of each of the m consecutive chips being connected to respective styli (51, 52) for marking image points with the same parity on each line.

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: A digital frequency sender comprises a generator which supplies multi-frequency codes by cyclically scanning a table under the control of a time base (BT). The sender comprises a logarithmic generator (GL) which delivers single-frequency signals, a logarithmic adder (AL) which sums two single-frequency signals in compressed form, and a frequency output unit (DF) controlled by a computer (CAL). The invention is particularly applicable to time division telecommunication exchange division.

Abstract: An alarm preprocessing logic system for use in a computer controlled digital switching exchange including a central computer, the alarm preprocessing logic system comprising defence modules each allotted to a respective portion of the exchange for detecting a plurality of types of alarm therein and including means for forwarding detected alarms via redundant alarm data transmission means (CAa, CAb, SLM1, SLM2, COL) to alarm processing logic including: means for confirming an alarm (PT2); means for attributing a category to received alarms depending on type of alarm and on the exchange unit which originated the alarm; and means for grouping alarms according to the category attributed thereto (PT1, MDI, MAP), and for classifying alarms in an order of priority; the alarm processing system further comprising data interchange logic connecting the alarm processing logic to the exchange central computer and arranged to ensure that alarms are sent to the central computer in their order of priority.

Abstract: A three-passage valve comprising (1) a body with a main passage (10) and two secondary passages (12,13), each of the secondary passages being fitted with a respective closure member (2,3) and the valve as a whole being provided with a single, common actuator unit (6) to operate the closure members in such a manner that the valve can occupy any one of three positions: a first position in which the main passage is in communication with a first one of the secondary passages while the other secondary passage is closed; a second, or intermediate, position in which both of the secondary passages are closed; and a third position in which said first passage is closed while the main passage is in communication with said other secondary passage.

Abstract: A phase noise correction circuit for a synchronous data transmission system using symbols and including a decision circuit (33) at its receiving end for supplying an estimate of the transmitted symbols on the basis of the received symbols, wherein said correction circuit comprises a phase shifter circuit (36) located at the receiving end ahead of the decision circuit (33) and provided with a third-order phase-controlling feedback circuit (37) comprising:a phase shift angle generator (62) having an incrementation input and providing the phase shifter circuit (36) with the value of a phase shift angle updated at the rate at which the symbols are received,a phase error detector (60) providing the value of the phase error between the received and the estimated symbols appearing at the terminals of the decision symbols, likewise at the rate at which the symbols are received; anda filter (61) interposed between the output of the phase error detector (60) and the incrementation input of the phase shift angle generat

Abstract: The invention relates to a helium leakage detector. It includes a measuring spectrometric cell (8) disposed in parallel with a molecular diffusion pump (6) whose outlet (7) is short-circuited at the inlet (5) by a pipe (10) upstream from a constriction (11) constituted by an adjustable valve.

Abstract: The present invention is concerned with maintaining the power supply to equipments along at least a section of a transmission line in the event of said line being cut. Each equipment (5) along the line (1) is provided with a local power supply circuit (6,7,9) inserted in the remote power supply loop at the equipment under consideration. A looping impedance (10) is connected in series with the break contacts (11,12) of a controlled switch and parallel across the power supply loop in such a manner as to create a partial power supply loop through the local power supply circuit when the switch is closed. Control means are provided to close the switch in the event of a power failure in the local power supply circuit, and to open the switch again only once the downstream side of the power supply loop draws current above a predetermined threshold value. The above circuit operates for a power supply loop that includes an energy source at one end (E) only of the transmission line.

Abstract: An echo canceller for a full-duplex carrier modulation transmission system terminal. The echo canceller includes a digital time-domain complex transversal filter with controlled weighting coefficients and an offset equal to a submultiple l of a Baud period .DELTA. related to a rate at which a stream of complex symbols is received at the input of the filter. These complex symbols include complex symbols outputted by a coder of a transmitter of the terminal at the rate l/.DELTA. interleaved with l-1 null symbols. The transversal filter output is connected to a digital modulator operated at the transmitter carrier frequency with instantaneous values updated at intervals equal to the Baud period to generate a passband echo copy signal. The invention is of particular benefit in transmission systems in which the product of the transmission carrier frequency and the Baud period is an integral multiple of l/4, as digital implementation of the modulator is then extremely simple.

Abstract: A control logic system comprising at least one sub-system including a master processor, two slave processors and an interchange memory which exchanges information between the master processor and the slave processors. The slave processors access a common memory via an interprocessor interface.

Abstract: A device for synchronizing multiplex lines in a time-division exchange comprising an input register, local and distant counters, a memory with a capacity of two frames, a frame alignment word detector, a write time select circuit, a decision circuit providing a frame skip or frame repetition facility for memory read operations, a circuit for addressing the memory in write and read modes and an odd parity injection circuit.

Abstract: A system for measuring the attenuation on a transmission path for a random signal in which the propagation time of said signal is between a lower limit T1 and an upper limit T2, the system comprising:a first maximum value indicator circuit with immediate response and a holding time not less than T2, to which the signal at the input end of said path is applied;a second maximum value indicator circuit with immediate response and a holding time not less than T2-T1, to which the signal at the output end of said path is applied;a detector which detects that the output of said first indicator has been maintained constant during a time interval not less than T2, connected to receive the output signal from said first indicator and determining times at which the indicator output signals are recognized; anda processor connected to receive the indicator output signals, controlled by said detector and generating a measurement signal which is a function of the instantaneous value of the ratio of the indicator output signa

Abstract: A feedback circuit for controlling the phase of a local oscillator provided with frequency adjusting means and delivering a local carrier wave for demodulating a data signal transmitted by single side band amplitude modulation, the said feedback circuit comprising at least one sign multiplier (21) producing the product of the sign of the local demodulation carrier shifted by a phase difference of .pi./4 multiplied by the sign of the data signal to be demodulated, followed by a sign coincidence auto-correlator (22) which controls the said frequency adjusting means and correlates two versions of the signal delivered by the sign multiplier (21), one of the two versions being delayed relative to the other by an odd multiple of one fourth of the period of the carrier used for the amplitude modulation on transmission.

Abstract: The present invention consists in a system for exchanging encoded messages between stations, in which each station comprises a connection module (2) connected to a signal bus (LMS) and to a data bus (LMI), the signal and data buses being serial multiplex links synchronized by a general timebase, a time interval comprising consecutive even-numbered and odd-numbered time slots being allocated in each signalling frame to each connection module. In this system for exchanging encoded messages, the signal and data buses are duplicated for security reasons, signalling messages being sent simultaneously on both signal buses and data messages being sent simultaneously on both data buses, messages being received on one bus only.

Abstract: A locking device for a two part plug-in connector comprises two separate locking pieces (10,20), one mounted on one part of the connector and including hooks, the other mounted on a second part of the connector and comprising hook-receiving notches. One or other of the locking pieces (10,20) is movable relative to its connector part.

Abstract: A multiplex connection unit for use in a time-division exchange comprising identical connection modules and a control interface connected to the control units of the exchange. A module comprises transcoders, synchronizing units (one per transcoder), a traffic distributor connected to the switching network, a signalling receiver and a signalling sender connected to the traffic distributor and to the control interface.