Abstract: A system and process for controlling the flow of packets carried by asynchronous time multiplex (EPACi) channels. The packets from one communication link are identified by their label and the identity of the multiplex channels which carries them. The process is comprised of allocating for each communication a predetermined clock rate and a predetermined threshold value, measuring the difference between the number of packets entering belonging to the communication and the number of pulses generated by the clock, lower bounding this difference, and, if the difference reaches a predetermined threshold, triggering a signal (DEP) which causes the detection of packets belonging to the communication in question as long as the difference is not less than the predetermined threshold.

Abstract: The invention relates to a process for the preparation of berlinite crystals AlPO.sub.4, with a high Q factor, from seeds or crystalline flakes of AlPO.sub.4, by a hydrothermal method. It is characterized in that the crystallization solution is a sulfuric solution of AlPO.sub.4. The invention also relates to the berlinite monocrystals obtained by this process.

Abstract: The radiating portion of the antenna is formed from two similar radiating doublets (1,3; 2,4) which are located in a single plane and are orthogonal, with the slots between driven elements of the doublets crossing one another at the center (C) of the unit antenna.The two doublet modules (1,3; 2,4) are associated with the central conductors of three-plate lines which are orthogonal, with their extensions crossing one another beneath the center (C) of the antenna. Each three-plate line consists of the plates (1,3; 2,4) of a doublet, on the one hand, a reflector, on the other hand, and between the plates and the reflector, the central conductor. The reflector is common to the two doublets.

Abstract: The packet flow of each virtual circuit is measured and compared to an allocated average value. At each transmission authorization request (DAE'), when found to be less than the average value, a positive difference brings about an authorization to transmit and is translated into a right to transmit which is proportional to the time span since the previous request, the right to transmit being accumulated. When it is found to be greater than the average value, a negative difference brings about, if the number of accumulated transmission rights is positive, on one hand, the authorization to transmit and, on the other hand, a decrementing of the accumulated number, and if the accumulated number is nil, a refusal of authorization to transmit.Some examples of systems carrying out the process are described.The process and systems are applicable in particular to packets carried by asynchronous time multiplexers.

Abstract: A switching system for switching synchronous and/or synchronous data blocks between incoming and outgoing multiplexes. The asynchronous blocks are sporadically carried in the multiplexes. The cost of the system is reduced owing to the use of a single buffer memory whose cells memorize indifferently synchronous and asynchronous blocks. The number of cells is lower than the product of the number of incoming or outgoing multiplexes and the number of blocks per frame in the multiplexes. A buffer memory managing and write addressing circuit derives and memorizes the occupied or free condition of each of the buffer memory cells thereby permanently selecting the address of one of free buffer cells in which a data block is to be written. The occupied condition of a cell is signalled responsive to the write of an incoming data block into this cell, and the free condition of the cell is signalled responsive to the last read of the written block.

Abstract: A resonant loop current disturbing probe. This probe comprises a conductive loop closed on a photoresistor, a light-emitting diode optically coupled to the photoresistor by an optical fiber and a diode control circuit. This probe is characterized in that it also comprises a variable capacitor connected in parallel to the loop. The loop-capacitor assembly forms a resonant circuit, the capacitor being adjusted in such a way that said circuit resonates at the frequency of the current to be disturbed. Application is to the measurement of the current in antennas.

Abstract: A fiber optic coupler for coupling 2.sup.n inputs and one output, n being an integer, comprising: two halves of a solid part formed with 2.sup.n -1 identical convex grooves parallel to a midplane and to a fractioning plane along which the part was separated into two halves. A plurality of optical fiber lengths are located each in one of the grooves, the halves and fibers are cut along a plane transverse to the midplane and fractioning plane at a depth selected for eliminating half of the cross-section of the fibers in the midplane. An auxiliary part formed with 2.sup.n -1 grooves having the same distribution as the 2.sup.n -1 grooves in the halves is retained in abutment against the halves, end portions of the fiber lengths being located in the grooves for optical coupling each with the end surfaces of two lengths, whereby 2.sup.n -1 elementary 2-to-1 elementary couplings are achieved.

Abstract: A wide band directional coupler for microstrip lines has a microstrip line ection whose conductive core is coupled to the core of the main line over a length .lambda./4 (.lambda. being the wave length in a mid portion of the desired pass band). The section has a first fraction parallel to the main line and at a small distance therefrom so as to provide tight coupling and a second fraction diverging from the main line and closed on a matching impedance. The free end of the first fraction is connected to the load and has an extension projecting over a length less than .lambda./16 for forming a microcapacitor tapping energy from the main line.

Abstract: The electrode structure comprises in each section three parallel microbands of identical width, the first and second microband covering first and second optical guides respectively and being separated by a width giving to the propagating line which they form a characteristic impedance equal to the required adaptation impedance; the third microband is far enough away from the second band for the contribution of the former to such characteristic impedance to be negligible. The covering of the first and second optical guides by the first and second microbands alternates from one section to the next section and the passage from a first section to a second section is obtained by a transition zone comprising inclined microbands.

Abstract: A videotex asynchroneous transmission system uses a parity bit for each character, with a continuous ARQ-type retransmission method. The data are transmitted in blocks (so-called "code words"). Each code word is comprised of a block of seventeen bytes "1"-"15" constituting the characters which are to be transmitted encoded by seven bits b1-b7. The 8th bit b8 of each byte is the parity bit. The 16th byte is the check byte of the code word, and the 17th byte being the enabling byte of the code word.