Abstract: Radio transmission of chronometric information. A device comprising an antenna (A1, A2) to which there are coupled on one hand a generator (G1, G2) generating a signal to be sent (e1, e2) and a reception processing circuit (C1, C2), capable of processing a received signal (r1, e2) where the signals exchanged have the same carrier frequency. Separate time segments are generated with successive random positions. Transmission is enabled only during these time segments, whilst reception is enabled only outside these segments, making it possible to use the time markers of the signals without any effect of recurrent masking of the reception signal by the transmission signal.

Abstract: A device for the alignment of a laser beam amplification system comprises at least measuring means and alignment templates positioned instead of filtering hole plates of the amplification system, the alignment templates having holes whose centers have substantially the same spatial positions as the centers of the filtering holes, certain template holes being provided with reference sights offset in an angular way with respect to one another, the tips of these sights being pointed towards the center of the holes, the measuring means defining, by sighting at the end of the amplification system, the divergences between the focusing points of the beam in the holes, merged at a single point, and the tips of the sights, their angular positions enabling them to be assigned to their respective holes, the positions of elements of the amplification system being then controlled as a function of the measurements of divergences.

Abstract: A navigation system having a terminal provided at each mobile station. Each terminal includes a locator for locating a mobile station, a display for displaying its travel relative to the reference direction, an indicator to indicate a common reference direction to both mobile stations with the indicator being coupled to the display, a travel data communicator and a processor to process data from the indicator, the locator and the communicator and display it on the display. At least one of the two mobile stations further includes a display for displaying the travel of the second mobile station relative to the first and an input unit for inputting a predetermined angle for defining how the direction of travel of the second mobile station should be corrected relative to the new direction of travel of the first mobile station. The correction is transmitted to the second mobile station by the travel data communicator of the first and second mobile stations.

Abstract: This device comprises an optical source emitting a single-wavelength light beam. An index grating has been recorded in a holographic device by the interference of two plane light beams, both being beams at a single wavelength with one and the same determined value and being concurrent in the holographic device. The holographic device is illuminated by the light beam and delivers a single-wavelength beam whose radiation pattern has a limited angular passband. The wavelength of the reading beam may be different from that of the recording beams. Its orientation is then different from that of the beams.

Abstract: The invention provides a method for forming a semiconductor device having several gate levels, which, in the case of forming a device with two gate levels, comprises the following steps:1. on a semiconductor substrate are deposited a dielectric layer, then a layer of material in which the gates of the first level are to be formed and a dielectric layer;2. the gates of the first level are formed by etching the two upper layers;3. the sides of the gates of the first level are isolated;4. a second layer is deposited of material in which the gates of the second level are to be formed;5. in this second layer an opening is formed giving access to the dielectric layer covering the top of the gates of the first level;6. by plasma etching or by chemical etching the zones of said second layer which overhang the gates of the first layer are removed by etching them simultaneously on their internal and external faces.

Abstract: In an antenna of the Cassegrainian or Gregorian type including a periscope arrangement, the auxiliary reflector has a longer focal distance than the auxiliary reflector of a conventional antenna of this type and the length of the optical path between the auxiliary reflector and the primary source of the antenna is choosen substantially equal to the distance between the auxiliary reflector and that one of its two foci which is the more remote therefrom. This makes it possible to use only plane mirrors in the periscope arrangement.