Abstract: Traffic simulator for tandem exchange testing. The simulator comprises a calling side module (CAM) to simulate a calling exchange, with facilities for the selection of dialling information, type of test operation and signalling code and connected to the tandem exchange (CT) at an i/c circuit terminating equipment (JA) of a type suited to the selected signalling code; answering side module (CAV) to simulate a called exchange, connected to the tandem exchange at an o/g circuit terminating equipment (JD) and comprising means for selection of the signalling code for communication with said terminating equipment, said two modules being independent and signal flows between them passing exclusively through the tandem exchange.

Abstract: A programmable sequential logic circuit processes data according to a prom containing instructions of different lengths, each instruction composed of one or several words. The sequential logic circuit comprises a memory containing the instructions and data words, an arithmetic and logical processing unit (ALU), and an instruction register for temporarily storing an instruction word read from the memory. An adder is connected to index the contents of address registers by adding the contents of one of a plurality of data registers. A system clock circuit driven by a clock and an operation code in the instruction register to control the operation of the sequential logic circuit. Access to the ALU is through an input multiplexer inputs of which are connected to the output of the memory and the outputs of the data registers and of the address registers. The output of the ALU is connected to an output bus via a circuit having outputs which adopt a high impedance state when they are not enabled.

Abstract: The invention relates to a reduced redundancy facsimile transmission installation which includes at the transmission end means which form run length words from the binary data analysis of a document.In accordance with the invention, at the transmission end, an array of combinatorial logic circuits (26), preferably of the PLA type, is programmed to transcode run length words into other words, using a truncated Huffman code and, at the receiving end, arrays which are also preferably of the PLA type provide inverse transcoding.Application: facsimile transmission.

Abstract: The present invention relates to switching wide band electric transmission signals. It provides a switching matrix which includes inlet/outlets one of which sets forms the columns while the other set forms the rows of the matrix and switching points disposed at the intersections of the conductors. The wiring of the matrix includes plane supports equal in number to that of its rows and of its columns, each row conductor or column conductor being wired on a distinct support, the supports being assembled in two stacks disposed perpendicularly to each other, one stack being constituted by the wiring supports of the column conductors while the other is constituted by the wiring supports of the row conductors. The figure shows a set of two stacks 204, 205, of four supports in individual screen boxes which form a switching matrix with four rows and four columns. Such a matrix is used advantageously for switching telecommunication signals.

Abstract: A control signal x(t) of known characteristics is transmitted over a transmission channel (1) together with a useful signal y(t).

Abstract: A loudspeaking telephone has a differential coupler (3) connecting a two-way two-wire telephone line (4) to separate transmission and reception channels (1 and 2 respectively) including respectively a microphone (5) and a loudspeaker (7). A first transversal filter (10) synthesizes an acoustic echo signal ya which is subtracted from the microphone signal to deliver a substantially echo-free signal to the transmission channel. Likewise a second transversal filter (11) synthesizes an electrical echo signal to deliver a substantially echo-free signal to the reception channel.

Abstract: Device for inserting several bits in a rhythmed digital train, comprising a osed looped shift register, the shift being controlled according to the rhythm of the train. The register receives, in parallel, the bits to be inserted, the write-in locations depending on the instant at which it is required to have these bits available in order to insert them in the train. Preferably, the train being subdivided into sub-groups (IT) of adjacent bits, the register comprises as many bistable elements as there are bits in a sub-group.

Abstract: The invention is characterized by connectors 17, 18, connected by a plug-ended cord 15, it being possible to prewire and wrap the assembly in the factory, to connect a distribution frame 11 to a connector 18.The contacts in the connectors are disposed on juxtaposed terminal strips each of which includes two rows of contacts, this allowing semiautomatic connections.

Abstract: Apparatus for reducing the intermodulation noise generated in a chain of amplifiers. The apparatus includes a first phase-shift circuit for at least partially compensating for the phase distortion and phase jumps in the chain and a balancing circuit including a source of compensating noise.The compensating noise is inverted, then added to the original signal to cancel the distortion generated in the chain. In one embodiment, the source of the compensating noise is a series of amplifiers and phase-shift networks which simulate the transmission characteristics of the actual amplifier chain.

Abstract: The invention comes within the field of half echo-suppressor for four-wire telephone lines and relates more particularly to the transmitted speech detector, said suppressor comprising an accumulator for accumulating characteristic indices of the samples, to control of the blocking element in the send channel depending on the accumulated value.In accordance with the invention, there is provided at least one digital comparator with a threshold, which receives the content of the accumulator and whose threshold is fixed between the limits of the accumulator. The blocking element can therefore be controlled with several operation times and via different hold circuits.

Abstract: An electro-mechanical filter comprises an inlet electro-mechanical transducer (12) an outlet electro-mechanical transducer (14) and a mechanical filter constituted by a series connection of resonator bars (1 to 11) which are interconnected by couplers (20 to 29). The bars are half a wavelength long at the central frequency of the pass-band while the couplers are one-quarter of a wavelength long. Instead of being connected to the ends of the bars, the couplers are connected to recessed stepped flats (40) located near the ends of the bars. The positions of the flats (40) are determined to be close to nodes in the first few orders of partials in bending mode vibration of the bars. This has the effect of greatly attenuating the excitation of such parasitic bending modes of vibration. Clearance to enable the couplers to reach the flat (40) is provided by a more deeply stepped positioned flat (41) extending to the end of the rod. Such filters may be used in terminals for analogue transmission systems.

Abstract: Two main rectangular wave guides e.g. for telecommunications in GHz frequency bands are coupled by arms inclined for example at 60.degree.. This simultaneously simplifies machining of the coupler in the form of two symmetrical shells and also improves the electrical characteristics of the coupler.

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: A document analyser for analyzing a document along successive analysis lines as the document moves past the generally stationary analyzer. The analyzer illuminates said document along an analysis line, optically a sensor receives the image of the analysis line which is projected onto the sensitive surface of the sensor. In accordance with the invention, an optical element and the sensor are optically aligned and held rigidly in relation to one another by a common rigid support which is stirrup-shaped and with which they constitute a preset optical assembly. Application to transmission of facsimile signals.

Abstract: Low-level, wide-band signals e.g. for use in telephone transmission are switched in a matrix device. The overall matrix is subdivided into elementary matrices of smaller size and each inlet of the overall matrix is provided with a selector for selecting the appropriate elementary matrix which contains the desired cross-point. This subdivision is performed as is conventional to reduce interference and attenuation from echos generated in the unused portions of the matrix, but it has the drawback of increasing the complexity of switch control, two selectors and one cross-point needing activation in the place of a single cross-point. The present invention provides selectors which are sensitive to the conductive state of the cross-points to which they are directly connected to repeat the conductive condition to their respective inlet of the overall matrix, thereby simplifying switching control without sacrificing transmission characteristics.

Abstract: Ringing current is a high-voltage, low-frequency signal which is sent from a telephone exchange via a pair of wires to ring a bell in a distant telephone. It is becoming common practice for distant telephones to be connected via a carrier connection and the present invention provides a device for conveying a high-voltage low-frequency signal along such a carrier connection. The device comprises a sender part and a receiver part connected together by the carrier connection. The sender part on/off modulates one of the carrier frequencies used in the connection at twice the rate of the low-frequency signal. The receiver part detects the on/off modulation and uses it to connect alternate opposite voltages delivered by a voltage multiplier circuit to a line connected, for example, to a telephone bell.

Abstract: The invention consists in an equalization system with two sections, one at each end of a transmission channel. The section at the transmission end adds control signals to information signals to be transmitted over the line. The section at the reception end generates control signals identical to those added at the transmission end and in phase with the control signals received over the transmission channel, which are separated from the received information signals by means of a first transversal filter with controllable weighting coefficients, the reciprocal transfer function of the transmission channel being synthesized from the locally generated and the received control signals by means of a second transversal filter with controllable weighting coefficients, equalization being achieved by means of a third transversal filter with the same design and same weighting coefficients as the second transversal filter. The invention is applicable to the transmission of data over telephone lines.

Abstract: The present invention relates to a facsimile transmission installation adapted to allow rapid transmission of the contents of forms. In accordance with the invention, various types of blank forms are memorized and the transmission equipment includes a comparator connected to a memory and to an analysis circuit and allows the transmission of a facsimile signal which represents only the data added on the analyzed filled-in form and the reception equipment includes a text regenerator which operates from a transmitted facsimile signal and from a signal which comes from its memory.

Abstract: An object pattern to be inspected, such as a printed circuit board, and a reference pattern are scanned synchronously by respective cameras. The outputs of the cameras are compared and a fault signal is produced when the outputs do not coincide.

Abstract: The invention relates telecommunications. It concerns in particular the cutting of optical fibre. It provides a hand tool which is generally shaped like pincers whose two legs move apart during operation, the optical fibre being fixed to each of the free ends of the legs which stretch it and press it against a rounded forming part fixed to one of the legs while a knife comes up to the forming part to start breaking the fibre by scoring it, all these operations being controlled by operating a single trigger lever. It applies to the forming of connections at the ends of the optical fibres.