Abstract: A base station constructs CDMA channels, each defined by a respective spreading sequence which modulates information bits to be transmitted for forming a respective channel signal. The different channel signals are combined, and then modulated on a carrier frequency, so as to produce a phase shift keyed radio signal which is transmitted towards mobile stations. Each spreading sequence has only one real component. For producing the radio signal, a relative phase shift is applied between different channel signals.

Abstract: A synchronization method includes selecting, at a mobile station, at least one periodic pseudorandom sequence (PN) which corresponds to, and is synchronized with, the reference sequence transmitted by a base station on a pilot channel, and received by the mobile station over a propagation path, this operation being carried out regardless of the frequency deviation between the transmitter and the receiver. Various possible sequences are tested by calculating the quantities E[s(t).multidot.s*(t-.tau.)] and E[s(t).multidot.s*(t)], where E[.multidot.] designates the mean value calculated over a predetermined integration time, .tau. designates a predetermined delay, and s(t)=r(t).multidot.c(t) designates the product of the received base band signal r(t) and the value (c(t)) of the tested sequence, and by calculating the ratio .vertline.E[s(t).multidot.s*(t-.tau.)][.vertline./Es(t).multidot.s*(t)]. The sequence under test is selected if the ratio exceeds a predetermined threshold.

Abstract: The method is used to transmit digital signals by radio over a predefined frequency band between a base station and mobile stations. At least one repeater station is used to receive radio signals transmitted by the base station and to retransmit radio signals to the mobile stations over the same frequency band. The spectrum of the radio signals transmitted by the base station to the repeater station is reversed relative to the spectrum of the radio signals retransmitted by the repeater station to the mobile stations. The invention is particularly applicable to radiotelephone communications networks.

Abstract: Each path is identified by a delay which is applied to at least one spreading sequence for determining a correlation between the received signal ans said spreading sequence. For each selected delay, a reception energy, contained in the CDMA signal consisting of a correlation between the received signal and a reference spreading sequence, is estimated. Delays to be tested are randomly chosen with a choice probability having a maximum for a delay substantially equal to the smallest selected delay. The delays thus chosen are tested by estimating the reception energy associated thereto. When the reception energy for a tested delay is greater than at least one of the reception energies associated to the previously selected delays, the tested delay is substituted for the previously selected delay having the smallest reception energy.

Abstract: In order to establish a videophone communication from a calling terminal to a called terminal, a communication is established on a first TBCC channel, then a ringing tone is emitted automatically, from the called terminal, to the calling terminal on the first channel and a call is emitted to the telephone set on the second channel B; in response to the unhooking of the telephone handset the two channels are automatically linked from the called terminal; and, in response to a code from the telephone set, the emission is caused of a waiting tone to the calling terminal and a ringing to the called videophone terminal; in the event of acceptance on the part of the subscriber of the called videophone terminal, the establishment of communication is automatically continued in response to the hooking of the set.

Abstract: The method is for generating a digital multiplex signal for broadcasting. The multiplex is made up of packets of determined length coming from a plurality of sources, by applying a treatment selected from those belonging to a catalog of stored treatments. It is applicable to D2-MAC/packet and digital TV. An encoder implementing the method has sources in which the identity of the treatment to be performed is inserted in a field provided for this purpose in each packet precursor. Downstream from the sources, the encoder comprises a treatment unit for decoding the field and for causing the treatment defined by the field to be applied.

Abstract: According to the method, a physical transmission channel is split into a plurality of logic channels which may be dedicated to different communications. Each logic channel consists of time slots having a same duration and the same rank in successive frames of constant length. At least one of the logic channels is split into a plurality of sub-channels dedicated to different communications. Groups of k successive time slots (k being an integer greater than 1) are allocated to each logic sub-channel. The groups are time distributed in a regular way and k is so selected that N be different from (m.k+1) where m is an integer and N is the number of time intervals necessary for reconstructing an information block.

Abstract: A X-MAC encoder enables a plurality of components to be encoded, each having a sequence of packets, with the packets being distributed in successive bursts each occupying a predetermined fraction of a television frame line. It comprises a plurality of blocks each having at least one packet encoder provided with a buffer memory for storing digital data coming from a source, and an encoder for distributing the packets in bursts of adjustable duration not greater than the duration of one television line. A base encoder assembly contains a programmable device for allocating a determined window of the television frame to each block. It calls a burst of length corresponding to the width within the window that is allocated by the programmable device, on the basis of the respective block burst encoder, at the beginning of each window in a line.

Abstract: The ringer comprises a loudspeaker receiving signals from an amplifier, the amplifier having both a power supply input connected to a ringer line providing a ringer signal via a chopper power supply means, and a melody input which is connected to the ringer line via a regulation unit that provides an image signal representative of the power of the ringer signal, and via a transformation unit that transforms the image signal by means of a melody signal applied to a terminal.

Abstract: The multiplexing device is for insertion of digital packets, supplied by several different sources, in a same transmission channel having an average data rate at least equal to the sum of the average data rates supplied by the sources. It comprising a packet call input unit connected to the transmission channel. The sources are cascaded and the downstream source constitutes an interface towards the input unit. Each source comprises a generator of an insertion priority order for each packet as a function of the type of packet, of the number of stored packets, and of insertion rules associated with the type of packets to be transmitted. Each cascaded source, with the exception of the most upstream source, has a routing circuit supplying at its output the highest priority among the two priorities applied to its input, and of which one corresponds to the source itself and the second to the upstream unit.

Abstract: The relay base of the invention comprises a receive antenna connected to a receiver coupling member associated with receiver members connected to respective digital processing units. The digital processing units are connected to transmitter members via link lines each of which is associated with one of the digital processing units and all of the transmitted members via parallel connections, each transmitter member including a switching member causing one of the link lines to be put into communication with the associated transmitter member.

Abstract: A process for the pseudo-synchronization of a time multiplexing communication network comprises the steps of measuring a time shift TM in reception by a mobile station of synchronization signals from first and second fixed stations, measuring the propagation times t1 and t2 of a synchronization signal between the fixed stations and the mobile station, and calculating the transmission time shift TR between the synchronization signals in accordance with the relationship TR=TM+t1 -t2. The pseudo-synchronization process can also be employed for geographically locating a mobile station.

Abstract: A narrow pulse generator comprises a first transistor and a second transistor connected to a stabilized power supply via respective impedance-matching resistance. The first transistor has an input terminal connected to a source of signals having a series of voltage edge, an output terminal connected firstly to an inductance and secondly to a control terminal of the second transistor, and a control terminal connected to an input terminal of the second transistor. The second transistor has an output terminal connected to a load resistance and to an output terminal of the pulse generator.