Alcatel Cit

Compagnie Industrielle Des Telecommunications Cit-alcatel

Francois Marcel

Serge Allaire

Pierre Dore

Dany Sallaerts

Serge Surie

Charles Eldering

Alain Manoury

Opto-electronic transducer device for optical link termination equipment

In a method of allocating time slots for transmission in a half-duplex time division multiple access point-to-multipoint bidirectional transmission system enabling transmission between a central station and a plurality of remote stations at least one time slot is allocated to each remote station and to each transmission direction. The set of all time slots used for transmission from the central station to the remote stations are grouped into downward frames and the set of all time slots used for transmission from the remote stations to the central station are grouped together in upward frames. The origin time of the upward frame is chosen in each remote station so that in the central station the origin time of the frame is separated from the end time of downward frames by a period less than twice the transmission time between the remote station and the central station, whereby there is defined in the remote station an overlap area between upward and downward frames. The time slots are allocated in such a way as to avoid any coincidence between time slots allocated to the same remote station in the upward and downward frames, respectively, in the overlap area.

Method for allocating time slots for transmission in a half-duplex time

A method for determining the transmission time between remote terminal stations and a central terminal station in a point-to-multipoint bidirectional transmission network. The central station measures the time interval between a reference time for sending of information signals by the central station and reception by the central station of a location signal sent by a remote station after a time-delay starting from a reference time for reception of information signals by the remote station so that the location signal is received by the central station in a predetermined location window not assigned to reception of information signals by the central station. For a given remote station the time-delay is variable from an initial value such that the location signal is not necessarily received in the window and the location signal sending by the remote station is then repeated until the location signal is received by the central station in the window.

Method for determining the transmission time between remote and central

This power supply is intended, more particularly, for powering a user digital terminal from a remote terminal in an integrated service digital telephone network. It comprises a main D.C. electricity power source (10) provided with a protection device (11) causing its output to go to a high impedance state in the absence of a voltage across its terminals, and an auxiliary D.C. electricity power source (20) connected in parallel and in opposition with the main source (10) and provided with a current limiting device (20) which is normally tripped by the additional current which the main source (10) attempts to impose thereon.

Emergency D.C. power supply with the emergency state being indicated by

A timing recovery circuit for synchronous data transmission using a signal which, in the baseband, is formed by a succession of two-level signal elements, without overlap, and of duration T, able to take one of the four forms defined by the functions: ##EQU1## comprises a transition selection circuit. This circuit selects transitions in the received signal, in the baseband, separated from those which immediately precede them by a time-delay situated in an arbitrary range. This range brackets a symbol duration of between 3/4 and 5/4 times, exclusive, the duration of a signal element. A timebase which is synchronized on the transitions selected by the selection circuit delivers the signal element recovered timing.

Timing recovery circuit for synchronous data transmission using

The invention concerns a digital coder subject to a compression law having multiple linear segments with slopes decreasing in geometrical progression having a ratio of 1/2, in which a chain of threshold detectors in a linear progression is used a first time to determine the number of the segment, then a second time to determine the position of the level on the segment.

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Orsay, France

Francois Marcel