Abstract: The useful signal of a sampled video line is, at least partially, spliced to two adjacent segments (AB, BC), each of which has at least two states. The splicing point (B) between the two segments is synchronously defined in a pseudo-random manner at transmission and reception. Upon transmission, at each line and in a pseudo-random manner, one of two possible scrambling schemes is selected. The first scheme involves local reversing of the second segment, and the second scheme involves a reversing of the second segment followed by a permutation with the first segment. Upon reception, the processing is the inverse of the processing which occurred at transmission and is applied in order to reintroduce intelligibility to the video signal. That is the locally reversed segments are received and reversed, following the permutation used at transmission. The process applies to a MAC signal.

Abstract: An antenna array with circular symmetry made up of an array of cylindrica shaped printed circuit elementary antennas. It is made up of small radiating sources which are placed in superposed circles on a cylindrical surface. The sources are distributed at constant angular intervals on the circles. They have little coupling between themselves. On each circle of sources, they are energized in phase and with the same amplitude. An angular phase shift can be provided between the group of sources on a circle and those of another circle. The antenna can be energized by a three-layer printed circuit line. It can be made up by an array of doublets folded into sheets. Inside the cylinder the transmitter is installed to which is applied a signal to be transmitted and which supplies the modulated carrier to the array of radiating sources.

Abstract: One chip microprocessor, which is more particularly designed to execute culation algorithms of a public code encoding system formed by a public function and a secret inverse function of the type comprising at least one programmable read-only memory, a processing unit and an input/output device, wherein it comprises a memory, in which is recorded at least one algorithm corresponding to the performance of said secret function, and wherein the programmable read-only memory contains the secret parameters constituting the secret code and recorded in an area of the read-only memory which is inaccesible from the outside, the processing unit including the multiplying circuits necessary for the execution of the algorithm.

Abstract: In a system for broadcasting data in combination with a television signal, he emitting station broadcasts, sets (blocks) of data which may be in-coming from several paths, the sets of data being time multiplexed. The present invention makes it possible to use the same television broadcast system, regardless of the television standards which may be used, with a minimum of modifications in the conventional television receivers. The frequence of the binary elements used to transmit data is made to vary as a function of the band width of the television signal which in turn, corresponds to the TV broadcast used in the area where the data is broadcast.

Abstract: Videotex system provided with protection means against transmission errors.It can be used in the transmission and display of data on television recers for entertainment, information or instructional purposes.