Elastic waves device for memorizing information
AssigneeThomson-CSF
InventorsPierre Tournois, Charles Maerfeld
Life of this patent
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Abstract
A device for memorizing information by means of interactions between elastic waves and electromagnetic waves. It comprises a piezoelectric substrate, at least one electromechanical transducer receiving the information to be memorized, means for exciting a pulsating electric field through the substrate, said field interacting non-linearly with the elastic wave created by the transducer to form a spatial charge pattern representing said information and means for modifying the physical properties of the medium of propagation of the elastic waves in the region of said pattern, for memorizing. The reading is effected by a non-linear interaction between said pattern and the pulsating electric field.
Claims24
A device for memorizing information employing elastic waves, comprising:
- a piezoelectric substrate;
- at least one electromechanical transducer deposited on a surface of said substrate, receiving said information in the form of an electric signal and emitting a first elastic wave;
- first means for exciting a first electromagnetic field through the substrate, said electromagnetic field interacting with said elastic wave so as to produce a time-independent spatial charge pattern in said substrate, representing said information;
- means for fixing said pattern in said substrate;
- means for reading said information, constituted by second means for exciting a second electromagnetic field through the substrate, said second field interacting with said pattern so as to produce a second elastic wave, termed a reading wave, having the same characteristics as said first elastic wave but propagating in the opposite direction towards said transducer, said transducer generating an output electrical signal when receiving said reading wave, said output signal representing said information.
A method for memorizing an electric signal by means of an acoustic wave device, said device being of a type that includes:
- a piezo-electric substrate;
- at least one electromechanical transducer deposited on a surface of said substrate for generating elastic waves;
- means for exciting electromagnetic fields through said substrate;
- means for fixing a charge pattern within said substrate;
- said method comprising the steps of:
- producing a first interaction between a first wave, generated by said transducer when receiving said electrical signal to be memorized, termed the first signal, and a first electromagnetic field corresponding to a second electric signal, said first interaction generating a time-independent spatial charge pattern in said substrate, representing said first signal, said pattern being fixed by said fixing means;
- and
- producing a second interaction between said pattern and a second electromagnetic field, corresponding to a third electric signal, said second interaction generating a second elastic wave, termed the reading wave, having the same characteristics as said first elastic wave but propagating in the opposite direction towards said transducer which generated said first wave.
A method of memorizing a plurality of independent signals by means of an acoustic wave device, said device being of a type that includes:
- a piezo-electric substrate;
- a plurality of independent electromechanical transducers disposed on at least one surface of said substrate for generating elastic waves;
- means for exciting electromagnetic fields through said substrate;
- and
- means for fixing a charge pattern within said substrate;
- said method comprising the steps of:
- generating a plurality of elastic waves respectively by said plurality of transducers, corresponding to said plurality of independent signals to be memorized;
- producing a first set of interactions between said elastic waves generated by said transducers when receiving said electrical signals to be memorized, termed the first signals, and a first electromagnetic field corresponding to a second electrical signal, said first interactions generating a time independent spatial charge pattern in said substrate, representing said first signals, said pattern being fixed by said means for fixing a charge pattern;
- and
- producing a second set of interactions between said fixed pattern and a second electromagnetic field corresponding to a third electrical signal, said second interactions generating a second elastic wave, termed the reading wave, having the same characteristics as said first elastic wave, but propagating in the opposite direction thereof towards transducers from which they were originally generated.
Dependencies are inferred from the claim text.