International Business Machines Corporation

Alain Croisier

Rene J Glaise

Christian A Jacquart

Andre E Desblache

A multipoint connection system adapted to operate in the time-division multiplex mode. The system includes an output link (21), connected to the output of a control station (10) and to the input of each of the work stations (WS-1, WS-2), and a U-shaped input link (22) one leg of which has its end connected to the input of the control station and the other leg (22-2) of which is terminated by an impedance (Z2) and is connected to the output of each work station. The signals on the output link and on leg (22-2) travel in the same direction, thereby eliminating the need to provide adjustable means of determining the transmission times specific to each work station.

Multipoint system for interconnecting work stations

A circuit for interfacing an AF line to a central unit makes use of an RF transformer Tr. Said transformer is so arranged that the source AF signal to be transmitted modulates an RF carrier generated in a primary winding of the transformer and the resulting modulated signal in the secondary winding is demodulated before being transmitted to a line which is thereby linked to the source.

Telephone line interfacing circuit with directional transfer of ringing

Arrangement allowing an input bucket brigade (BBD) stage to feed several other BBD stages in parallel with no loss of the signal transferred from the input stage to the subsequent ones. An input voltage corresponding to a charge quantity is stored in the second capacitor of the input BBD stage. The drain of the output transistor of the input stage is connected to a first BBD stage wherein the first capacitor is connected to the source electrode of the first transistor of a second BBD stage. The first transistors of both stages are controlled by the same clock pulses. When these transistors are turned on, the capacitors connected thereto are in series with the second capacitor of the input stage. Consequently, the same current will flow through these capacitors, which will thus store the same charges so that the charge representing the input voltage will be reproduced in the first capacitors of the two BBD stages connected to the input stage. Means are provided for grounding the terminal of the first capacitor in the first stage that is connected to the source of the first transistor in the second stage at the time the transfer of the duplicated charge takes place.

Device for reproducing the charge stored in an input capacitor in a

A data transmitting and receiving system in which data is transmitted by varying the phase and amplitude of a carrier, including a receiver which detects the data in a received signal while reducing the effects of noise components which alter the phase and amplitude of the received signal. An in-phase component and a quadrature component are derived from the received signal and are then rotated an angular amount which is a function of an estimated value of the phase error in the received signal. The rotated components are then compared with two sets of reference coordinates for selecting a pair of reference coordinates which have values closest to the values of the rotated in-phase and quadrature components, respectively. The estimated value of the phase error is derived as a trigonometric function of the rotated components and selected reference coordinates. The selected reference coordinates are indicative of the transmitted data.

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Cagnes-sur-Mer, France

Alain Croisier