Thomson-csf

Olivier Menager

Gerard Coussot

Bernard Desormiere

Gregoire Eumurian

Michel Van Den Driessche

Albert Courty

An elastic surface wave filter including on the surface of a plate, an emitting transducer, a surface wave coupler, and means for receiving the waves radiated by the coupler. The means for receiving includes two transducers each having two terminals with one terminal of each being in common with one terminal of the other. The common terminal serves as a phase reference and the voltages induced at the remaining terminals are in phase opposition to one another in the transmission band of the filter.

Elastic surface wave filter

A surface elastic wave filter in which Rayleigh waves experience only small attenuation and phase-shift, the number of radiating elements encountered by the surface wave during the wave propagation having a direction parallel to an axis xx through the filter, being restricted. The filter comprises at least one electromechanical transducer constituted by two metallic comb structures A and B whose teeth d.sub.A1, d.sub.A2, d.sub.A3 and d.sub.B1, d.sub.B2, d.sub.B3 are interdigitated and are arranged at either side of an axis yy in symmetrical fashion vis-a-vis a point M located upon said axis, at the center of the transducer. The filter can be used to the filtering of video-frequency signals in television circuits.

Surface elastic wave filter

The correlator comprises a piezo-electric substrate on the ends of which there are arranged two transducers supplied with two electrical signals and emitting two contra-propagating surface waves. The correlator furthermore comprises m processing channels supplied with electrical signals induced by the surface waves at m 'points' on the substrate which are distributed in the direction of propagation of the waves. Each channel comprises a non-linear device and an integrator furnishing a sample of the correlation function of the two signals.

Surface elastic wave analogue correlator

The present invention relates to surface elastic wave electromechanical devices. The electromechanical device in accordance with the invention comprises a central common transducer and two identical transducers interconnected electrically. The central transducer produces bi-directional radiation, and intermediate means are provided to selectively modify the propagation of the surface elastic waves.

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Paris, France

Olivier Menager