Thomson-csf

Yvon Fouche

Tristan De Couasnon

Serge Drabowitch

Philippe Elleaume

Raoul Monnier

Jean-Yves Eouzan

Jean-Bernard Rault

Gerard Auvray

Guy Desodt

Stephane Hergault

Serge Travert

Tristan D Couasnon

Jean Anastassiades

The present invention relates to a process for transmitting a digitized signal according to OFDM (Orthogonal Frequency Division Multiplexing) type multicarrier modulation using N orthogonal channels. In accordance with the present invention, the channels are divided into two, N/2 channels. corresponding to a first frequency band being sent via a first transmission track (,A,,A,,A,,A,,A) according to a first polarization and the remaining N/2 channels being brought back into the same frequency band and sent via a second transmission track (,B,,B,,B,,B,,B) according to a second polarization crossed with respect to the first.

Process for transmitting a digitized signal according to OFDM type multicarrier modulation, transmitter and receiver for the implementation of the said process

Method of binary encoding the points of a constellation used in a

Method of realigning the local oscillators of a receiver and device for

Transmitter, transmission method and receiver

A device and a method for the transmission or storage of data optimizing the use of the pass-band. Also, a method for transmission by phase modulation. In order to obtain high data throughput rates, the synchronization of a transmission clock with the reception clocks is used. This synchronization is gotten, for example, by transmission of a pseudo-random code and by the convolution or correlation of the received signals with the pseudo-random code. The invention also enables the elimination of multiple echoes by computation. The invention can be applied chiefly to the transmission of radio programs, television broadcasts or digital data.

Device and method for the data transmission or storage optimizing the

A data transmission and/or acquisition device and method are disclosed. The said device and method use two cross polarizations of an electromagnetic wave and a magnetic recording device. The invention pertains to phase/amplitude modulation using two phase-modulated signals transmitted on two orthogonal polarizations. At reception, the vector sum of the two signals is added taken. The resultant signal is amplitude-modulated and/or phase-modulated. The invention can be applied especially to television and radio transmitters, radars and telecommunications equipment.

Device and method for data transmission and/or acquisition using two

A projection display device is provided with a negative feedback chain designed to correct all the faults of the projected image, said faults resulting as much from the projection tubes and from their optic systems (geometrical or focusing faults) as from the differences between these tubes (faults in convergence, colorimetry or uniformity of brilliance). The negative feedback chain comprises a test chart generating means, a means to retake the entire projected image and means for the comparision of the signals coming from the test image and from the retaken image. Correction signals are prepared on the basis of this comparison and are applied to the different control circuits defining the projection characteristics. The disclosed device can also be used for the real-time follow-up of the adjustments obtained in a phase prior to the projection of the sequence of useful video images. The invention can be applied notably to video projectors, retro-projection display devices or beam-index tubes.

Projection display device with negative feedback loop to correct all the

An automatic defect correction drive utilizing feedback in an image display device. According to the present invention, during an acquisition phase, a test image constituted of bright points of known positions distributed on a screen is displayed. This displayed image is then analyzed via an image acquisition device, to deduce from it the scanning, focusing and amplitude corrections to be applied to the display, so that the test pixels displayed on the screen have their expected positions and characteristics. These corrections are then interpolated for the intermediate pixels between test points, and then, during a continuation phase, these corrections are updated.

Process and device for image display with automatic defect correction by

Filter, phase-measuring device and method for application of said filter

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Chatenay Malabry, France

Yvon Fouche