Elastic surface wave device for treating high frequency signals
AssigneeThomson-CSF
InventorJean-Michel Autran
Life of this patent
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Abstract
The treatment is directly effected on the waves propagated. Zones, for creating interruptions in propagation, are created on the useful surface of the propagation material. Several parallel tracks for propagating the elastic waves are thus delimited by these zones, the length and width of which are selected in dependance upon the required treatment.
Claims12
An elastic surface wave device for treating high frequency waves forming a filter having a transfer function T(F) of which the inverse Fourier transform I (t), which is the pulse response of the filter, comprises n pulses identical in sign, phase-shifted relative to one another and of various amplitudes which comprises:
- A material for propagating said surface waves at a predetermined velocity v, on a useful propagation surface;
- input means delivering a front of acoustic waves to be treated to one end, the so-called input end, of the said useful propagation surface of said material;
- means, combined with said useful surface, for creating interruptions in propagation in zones where the propagation velocity v' is different from that v of said material, said zones delimiting n parallel tracks for propagating the elastic waves issuing from said wave front, the width of said zones being proportional to the amplitude of said n pulses and their relative lengths being proportional to the relative phase shifts of said pulses.
Dependencies are inferred from the claim text.